Hi
I have the following query
select studentid from students where studentid not in (select studentid from
coursestudent)
is there some way I could write this with using the 'not in'?
student is a table of students. coursestudent is a join table of courses to
students. I'm trying
to find those students who are not registered for a course. While the
above query works,
I'd like to find a more efficient query.
create table student
(studentid int identity primary key,
name varchar(50),
address1varchar(50),
address2 varchar(50),
city varchar(50),
state varchar(4),
zip varchar(11))
create table coursestudent
(courseid int
studentid int)
notes:
- non clustered index on courseid and non clustered index on studentid exist
- there is a foreign key relationship from coursestudent's studentid to
student studentid
try:
select a.studentid from students as a
left join coursestudent as b on a.studentid = b.studentid
where b.courseid is null
Mikhail Berlyant
Eng.Manager
Yahoo! Music
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>
|||To determine which is most efficient, you need to look at the execution plans, examine the I/O, and execution times.
Here is an alternative:
SELECT StudentID
FROM Students s
JOIN CourseStudent c
ON s.StudentID = c.StudentID
WHERE c.StudentID IS NULL
Arnie Rowland, Ph.D.
Westwood Consulting, Inc
Most good judgment comes from experience.
Most experience comes from bad judgment.
- Anonymous
"Dodo Lurker" <none@.noemailplease> wrote in message news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>
|||Arnie
Please double-check - this shouldn't work
There should be left join
Mikhail Berlyant
Eng.Manager
Yahoo! Music
"Arnie Rowland" <arnie@.1568.com> wrote in message
news:ul7tQYQ4GHA.2144@.TK2MSFTNGP04.phx.gbl...
To determine which is most efficient, you need to look at the execution
plans, examine the I/O, and execution times.
Here is an alternative:
SELECT StudentID
FROM Students s
JOIN CourseStudent c
ON s.StudentID = c.StudentID
WHERE c.StudentID IS NULL
Arnie Rowland, Ph.D.
Westwood Consulting, Inc
Most good judgment comes from experience.
Most experience comes from bad judgment.
- Anonymous
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>
|||Why do you think the solution you have is not efficient?
In the pubs database, these two queries have an almost identical plan, but
the wone with the NOT IN is slightly cheaper:
use pubs
select pub_name from publishers
where pub_id not in (select pub_id from titles)
select pub_name
from publishers p left join titles t
on p.pub_id = t.pub_id
where t.pub_id is null
HTH
Kalen Delaney, SQL Server MVP
http://sqlblog.com
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
> from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
> to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
> exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>
|||> is there some way I could write this with using the 'not in'?
Another method is with NOT EXISTS. NOT IN and NOT EXISTS will both yield
identical execution plans (and performance) as long as the queries are
semantically the same. The SQL language is descriptive rather than
procedural so the optimizer will try to generate the most efficient plan
possible based on your query statement. As long as the expressions are
sargable, most performance tuning is in making sure you have appropriate
indexes.
However, note that the coursestudent.studentid column allows null so the
queries are not the same semantically. With not NOT IN query, no rows will
be returned if *any* null studentid exists in the coursestudent table. The
NOT EXIST query will return the stundents you expect.
If the coursestudent studentid column were changed to allow nulls, then both
NOT IN and NOT EXISTS queries will be semantically identical.
Hope this helps.
Dan Guzman
SQL Server MVP
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
> from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
> to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
> exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>
|||You are absolutely correct. I meant to include the LEFT on the join.
Arnie Rowland, Ph.D.
Westwood Consulting, Inc
Most good judgment comes from experience.
Most experience comes from bad judgment.
- Anonymous
"Mikhail Berlyant" <remove-this-berlyant@.yahoo-inc.com> wrote in message
news:OzbZqbQ4GHA.3592@.TK2MSFTNGP05.phx.gbl...
> Arnie
> Please double-check - this shouldn't work
> There should be left join
> Mikhail Berlyant
> Eng.Manager
> Yahoo! Music
> "Arnie Rowland" <arnie@.1568.com> wrote in message
> news:ul7tQYQ4GHA.2144@.TK2MSFTNGP04.phx.gbl...
> To determine which is most efficient, you need to look at the execution
> plans, examine the I/O, and execution times.
> Here is an alternative:
> SELECT StudentID
> FROM Students s
> JOIN CourseStudent c
> ON s.StudentID = c.StudentID
> WHERE c.StudentID IS NULL
>
> --
> Arnie Rowland, Ph.D.
> Westwood Consulting, Inc
> Most good judgment comes from experience.
> Most experience comes from bad judgment.
> - Anonymous
>
> "Dodo Lurker" <none@.noemailplease> wrote in message
> news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> from
> to
> exist
>
|||thank you everyone
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>
Showing posts with label write. Show all posts
Showing posts with label write. Show all posts
Tuesday, March 20, 2012
another way to write this query?
Hi
I have the following query
select studentid from students where studentid not in (select studentid from
coursestudent)
is there some way I could write this with using the 'not in'?
student is a table of students. coursestudent is a join table of courses to
students. I'm trying
to find those students who are not registered for a course. While the
above query works,
I'd like to find a more efficient query.
create table student
(studentid int identity primary key,
name varchar(50),
address1varchar(50),
address2 varchar(50),
city varchar(50),
state varchar(4),
zip varchar(11))
create table coursestudent
(courseid int
studentid int)
notes:
- non clustered index on courseid and non clustered index on studentid exist
- there is a foreign key relationship from coursestudent's studentid to
student studentidtry:
select a.studentid from students as a
left join coursestudent as b on a.studentid = b.studentid
where b.courseid is null
Mikhail Berlyant
Eng.Manager
Yahoo! Music
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>|||This is a multi-part message in MIME format.
--=_NextPart_000_0247_01C6E0CB.6186E090
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
To determine which is most efficient, you need to look at the execution =plans, examine the I/O, and execution times.
Here is an alternative:
SELECT StudentID FROM Students s
JOIN CourseStudent c
ON s.StudentID =3D c.StudentID
WHERE c.StudentID IS NULL
-- Arnie Rowland, Ph.D.
Westwood Consulting, Inc
Most good judgment comes from experience. Most experience comes from bad judgment. - Anonymous
"Dodo Lurker" <none@.noemailplease> wrote in message =news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> > I have the following query
> > select studentid from students where studentid not in (select =studentid from
> coursestudent)
> > is there some way I could write this with using the 'not in'?
> > student is a table of students. coursestudent is a join table of =courses to
> students. I'm trying
> to find those students who are not registered for a course. While =the
> above query works,
> I'd like to find a more efficient query.
> > create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> > create table coursestudent
> (courseid int
> studentid int)
> > notes:
> - non clustered index on courseid and non clustered index on studentid =exist
> - there is a foreign key relationship from coursestudent's studentid =to
> student studentid
> > > >
--=_NextPart_000_0247_01C6E0CB.6186E090
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
&
To determine which is most efficient, =you need to look at the execution plans, examine the I/O, and execution =times.
Here is an alternative:
SELECT StudentID =FROM Students s JOIN CourseStudent c ON s.StudentID =3D =c.StudentIDWHERE c.StudentID IS NULL
-- Arnie Rowland, =Ph.D.Westwood Consulting, Inc
Most good judgment comes from =experience. Most experience comes from bad judgment. - Anonymous
"Dodo Lurker" =wrote in message news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...> =Hi> > I have the following query> > select studentid =from students where studentid not in (select studentid from> coursestudent)> > is there some way I could write this =with using the 'not in'?> > student is a table of students. coursestudent is a join table of courses to> students. I'm trying> to find those students who are not registered for a course. While the> above query works,> I'd =like to find a more efficient query.> > create table =student> (studentid int identity primary key,> name varchar(50),> address1varchar(50),> address2 varchar(50),> city varchar(50),> state varchar(4),> zip varchar(11))> => create table coursestudent> (courseid int> studentid int)> > notes:> - non clustered index on courseid =and non clustered index on studentid exist> - there is a foreign key =relationship from coursestudent's studentid to> student studentid> => > >
--=_NextPart_000_0247_01C6E0CB.6186E090--|||Arnie
Please double-check - this shouldn't work
There should be left join
Mikhail Berlyant
Eng.Manager
Yahoo! Music
"Arnie Rowland" <arnie@.1568.com> wrote in message
news:ul7tQYQ4GHA.2144@.TK2MSFTNGP04.phx.gbl...
To determine which is most efficient, you need to look at the execution
plans, examine the I/O, and execution times.
Here is an alternative:
SELECT StudentID
FROM Students s
JOIN CourseStudent c
ON s.StudentID = c.StudentID
WHERE c.StudentID IS NULL
Arnie Rowland, Ph.D.
Westwood Consulting, Inc
Most good judgment comes from experience.
Most experience comes from bad judgment.
- Anonymous
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>|||Why do you think the solution you have is not efficient?
In the pubs database, these two queries have an almost identical plan, but
the wone with the NOT IN is slightly cheaper:
use pubs
select pub_name from publishers
where pub_id not in (select pub_id from titles)
select pub_name
from publishers p left join titles t
on p.pub_id = t.pub_id
where t.pub_id is null
--
HTH
Kalen Delaney, SQL Server MVP
http://sqlblog.com
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
> from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
> to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
> exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>|||> is there some way I could write this with using the 'not in'?
Another method is with NOT EXISTS. NOT IN and NOT EXISTS will both yield
identical execution plans (and performance) as long as the queries are
semantically the same. The SQL language is descriptive rather than
procedural so the optimizer will try to generate the most efficient plan
possible based on your query statement. As long as the expressions are
sargable, most performance tuning is in making sure you have appropriate
indexes.
However, note that the coursestudent.studentid column allows null so the
queries are not the same semantically. With not NOT IN query, no rows will
be returned if *any* null studentid exists in the coursestudent table. The
NOT EXIST query will return the stundents you expect.
If the coursestudent studentid column were changed to allow nulls, then both
NOT IN and NOT EXISTS queries will be semantically identical.
--
Hope this helps.
Dan Guzman
SQL Server MVP
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
> from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
> to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
> exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>|||You are absolutely correct. I meant to include the LEFT on the join.
--
Arnie Rowland, Ph.D.
Westwood Consulting, Inc
Most good judgment comes from experience.
Most experience comes from bad judgment.
- Anonymous
"Mikhail Berlyant" <remove-this-berlyant@.yahoo-inc.com> wrote in message
news:OzbZqbQ4GHA.3592@.TK2MSFTNGP05.phx.gbl...
> Arnie
> Please double-check - this shouldn't work
> There should be left join
> Mikhail Berlyant
> Eng.Manager
> Yahoo! Music
> "Arnie Rowland" <arnie@.1568.com> wrote in message
> news:ul7tQYQ4GHA.2144@.TK2MSFTNGP04.phx.gbl...
> To determine which is most efficient, you need to look at the execution
> plans, examine the I/O, and execution times.
> Here is an alternative:
> SELECT StudentID
> FROM Students s
> JOIN CourseStudent c
> ON s.StudentID = c.StudentID
> WHERE c.StudentID IS NULL
>
> --
> Arnie Rowland, Ph.D.
> Westwood Consulting, Inc
> Most good judgment comes from experience.
> Most experience comes from bad judgment.
> - Anonymous
>
> "Dodo Lurker" <none@.noemailplease> wrote in message
> news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
>> Hi
>> I have the following query
>> select studentid from students where studentid not in (select studentid
> from
>> coursestudent)
>> is there some way I could write this with using the 'not in'?
>> student is a table of students. coursestudent is a join table of courses
> to
>> students. I'm trying
>> to find those students who are not registered for a course. While the
>> above query works,
>> I'd like to find a more efficient query.
>> create table student
>> (studentid int identity primary key,
>> name varchar(50),
>> address1varchar(50),
>> address2 varchar(50),
>> city varchar(50),
>> state varchar(4),
>> zip varchar(11))
>> create table coursestudent
>> (courseid int
>> studentid int)
>> notes:
>> - non clustered index on courseid and non clustered index on studentid
> exist
>> - there is a foreign key relationship from coursestudent's studentid to
>> student studentid
>>
>>
>|||thank you everyone
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>
I have the following query
select studentid from students where studentid not in (select studentid from
coursestudent)
is there some way I could write this with using the 'not in'?
student is a table of students. coursestudent is a join table of courses to
students. I'm trying
to find those students who are not registered for a course. While the
above query works,
I'd like to find a more efficient query.
create table student
(studentid int identity primary key,
name varchar(50),
address1varchar(50),
address2 varchar(50),
city varchar(50),
state varchar(4),
zip varchar(11))
create table coursestudent
(courseid int
studentid int)
notes:
- non clustered index on courseid and non clustered index on studentid exist
- there is a foreign key relationship from coursestudent's studentid to
student studentidtry:
select a.studentid from students as a
left join coursestudent as b on a.studentid = b.studentid
where b.courseid is null
Mikhail Berlyant
Eng.Manager
Yahoo! Music
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>|||This is a multi-part message in MIME format.
--=_NextPart_000_0247_01C6E0CB.6186E090
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
To determine which is most efficient, you need to look at the execution =plans, examine the I/O, and execution times.
Here is an alternative:
SELECT StudentID FROM Students s
JOIN CourseStudent c
ON s.StudentID =3D c.StudentID
WHERE c.StudentID IS NULL
-- Arnie Rowland, Ph.D.
Westwood Consulting, Inc
Most good judgment comes from experience. Most experience comes from bad judgment. - Anonymous
"Dodo Lurker" <none@.noemailplease> wrote in message =news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> > I have the following query
> > select studentid from students where studentid not in (select =studentid from
> coursestudent)
> > is there some way I could write this with using the 'not in'?
> > student is a table of students. coursestudent is a join table of =courses to
> students. I'm trying
> to find those students who are not registered for a course. While =the
> above query works,
> I'd like to find a more efficient query.
> > create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> > create table coursestudent
> (courseid int
> studentid int)
> > notes:
> - non clustered index on courseid and non clustered index on studentid =exist
> - there is a foreign key relationship from coursestudent's studentid =to
> student studentid
> > > >
--=_NextPart_000_0247_01C6E0CB.6186E090
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
&
To determine which is most efficient, =you need to look at the execution plans, examine the I/O, and execution =times.
Here is an alternative:
SELECT StudentID =FROM Students s JOIN CourseStudent c ON s.StudentID =3D =c.StudentIDWHERE c.StudentID IS NULL
-- Arnie Rowland, =Ph.D.Westwood Consulting, Inc
Most good judgment comes from =experience. Most experience comes from bad judgment. - Anonymous
"Dodo Lurker"
--=_NextPart_000_0247_01C6E0CB.6186E090--|||Arnie
Please double-check - this shouldn't work
There should be left join
Mikhail Berlyant
Eng.Manager
Yahoo! Music
"Arnie Rowland" <arnie@.1568.com> wrote in message
news:ul7tQYQ4GHA.2144@.TK2MSFTNGP04.phx.gbl...
To determine which is most efficient, you need to look at the execution
plans, examine the I/O, and execution times.
Here is an alternative:
SELECT StudentID
FROM Students s
JOIN CourseStudent c
ON s.StudentID = c.StudentID
WHERE c.StudentID IS NULL
Arnie Rowland, Ph.D.
Westwood Consulting, Inc
Most good judgment comes from experience.
Most experience comes from bad judgment.
- Anonymous
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>|||Why do you think the solution you have is not efficient?
In the pubs database, these two queries have an almost identical plan, but
the wone with the NOT IN is slightly cheaper:
use pubs
select pub_name from publishers
where pub_id not in (select pub_id from titles)
select pub_name
from publishers p left join titles t
on p.pub_id = t.pub_id
where t.pub_id is null
--
HTH
Kalen Delaney, SQL Server MVP
http://sqlblog.com
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
> from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
> to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
> exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>|||> is there some way I could write this with using the 'not in'?
Another method is with NOT EXISTS. NOT IN and NOT EXISTS will both yield
identical execution plans (and performance) as long as the queries are
semantically the same. The SQL language is descriptive rather than
procedural so the optimizer will try to generate the most efficient plan
possible based on your query statement. As long as the expressions are
sargable, most performance tuning is in making sure you have appropriate
indexes.
However, note that the coursestudent.studentid column allows null so the
queries are not the same semantically. With not NOT IN query, no rows will
be returned if *any* null studentid exists in the coursestudent table. The
NOT EXIST query will return the stundents you expect.
If the coursestudent studentid column were changed to allow nulls, then both
NOT IN and NOT EXISTS queries will be semantically identical.
--
Hope this helps.
Dan Guzman
SQL Server MVP
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
> from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
> to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
> exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>|||You are absolutely correct. I meant to include the LEFT on the join.
--
Arnie Rowland, Ph.D.
Westwood Consulting, Inc
Most good judgment comes from experience.
Most experience comes from bad judgment.
- Anonymous
"Mikhail Berlyant" <remove-this-berlyant@.yahoo-inc.com> wrote in message
news:OzbZqbQ4GHA.3592@.TK2MSFTNGP05.phx.gbl...
> Arnie
> Please double-check - this shouldn't work
> There should be left join
> Mikhail Berlyant
> Eng.Manager
> Yahoo! Music
> "Arnie Rowland" <arnie@.1568.com> wrote in message
> news:ul7tQYQ4GHA.2144@.TK2MSFTNGP04.phx.gbl...
> To determine which is most efficient, you need to look at the execution
> plans, examine the I/O, and execution times.
> Here is an alternative:
> SELECT StudentID
> FROM Students s
> JOIN CourseStudent c
> ON s.StudentID = c.StudentID
> WHERE c.StudentID IS NULL
>
> --
> Arnie Rowland, Ph.D.
> Westwood Consulting, Inc
> Most good judgment comes from experience.
> Most experience comes from bad judgment.
> - Anonymous
>
> "Dodo Lurker" <none@.noemailplease> wrote in message
> news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
>> Hi
>> I have the following query
>> select studentid from students where studentid not in (select studentid
> from
>> coursestudent)
>> is there some way I could write this with using the 'not in'?
>> student is a table of students. coursestudent is a join table of courses
> to
>> students. I'm trying
>> to find those students who are not registered for a course. While the
>> above query works,
>> I'd like to find a more efficient query.
>> create table student
>> (studentid int identity primary key,
>> name varchar(50),
>> address1varchar(50),
>> address2 varchar(50),
>> city varchar(50),
>> state varchar(4),
>> zip varchar(11))
>> create table coursestudent
>> (courseid int
>> studentid int)
>> notes:
>> - non clustered index on courseid and non clustered index on studentid
> exist
>> - there is a foreign key relationship from coursestudent's studentid to
>> student studentid
>>
>>
>|||thank you everyone
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>
another way to write this query?
Hi
I have the following query
select studentid from students where studentid not in (select studentid from
coursestudent)
is there some way I could write this with using the 'not in'?
student is a table of students. coursestudent is a join table of courses to
students. I'm trying
to find those students who are not registered for a course. While the
above query works,
I'd like to find a more efficient query.
create table student
(studentid int identity primary key,
name varchar(50),
address1varchar(50),
address2 varchar(50),
city varchar(50),
state varchar(4),
zip varchar(11))
create table coursestudent
(courseid int
studentid int)
notes:
- non clustered index on courseid and non clustered index on studentid exist
- there is a foreign key relationship from coursestudent's studentid to
student studentidtry:
select a.studentid from students as a
left join coursestudent as b on a.studentid = b.studentid
where b.courseid is null
Mikhail Berlyant
Eng.Manager
Yahoo! Music
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>|||To determine which is most efficient, you need to look at the execution plan
s, examine the I/O, and execution times.
Here is an alternative:
SELECT StudentID
FROM Students s
JOIN CourseStudent c
ON s.StudentID = c.StudentID
WHERE c.StudentID IS NULL
--
Arnie Rowland, Ph.D.
Westwood Consulting, Inc
Most good judgment comes from experience.
Most experience comes from bad judgment.
- Anonymous
"Dodo Lurker" <none@.noemailplease> wrote in message news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.co
mcast.com...
> Hi
>
> I have the following query
>
> select studentid from students where studentid not in (select studentid fr
om
> coursestudent)
>
> is there some way I could write this with using the 'not in'?
>
> student is a table of students. coursestudent is a join table of courses
to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
>
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
>
> create table coursestudent
> (courseid int
> studentid int)
>
> notes:
> - non clustered index on courseid and non clustered index on studentid exi
st
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>
>
>|||Arnie
Please double-check - this shouldn't work
There should be left join
Mikhail Berlyant
Eng.Manager
Yahoo! Music
"Arnie Rowland" <arnie@.1568.com> wrote in message
news:ul7tQYQ4GHA.2144@.TK2MSFTNGP04.phx.gbl...
To determine which is most efficient, you need to look at the execution
plans, examine the I/O, and execution times.
Here is an alternative:
SELECT StudentID
FROM Students s
JOIN CourseStudent c
ON s.StudentID = c.StudentID
WHERE c.StudentID IS NULL
Arnie Rowland, Ph.D.
Westwood Consulting, Inc
Most good judgment comes from experience.
Most experience comes from bad judgment.
- Anonymous
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>|||Why do you think the solution you have is not efficient?
In the pubs database, these two queries have an almost identical plan, but
the wone with the NOT IN is slightly cheaper:
use pubs
select pub_name from publishers
where pub_id not in (select pub_id from titles)
select pub_name
from publishers p left join titles t
on p.pub_id = t.pub_id
where t.pub_id is null
HTH
Kalen Delaney, SQL Server MVP
http://sqlblog.com
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
> from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
> to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
> exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>|||> is there some way I could write this with using the 'not in'?
Another method is with NOT EXISTS. NOT IN and NOT EXISTS will both yield
identical execution plans (and performance) as long as the queries are
semantically the same. The SQL language is descriptive rather than
procedural so the optimizer will try to generate the most efficient plan
possible based on your query statement. As long as the expressions are
sargable, most performance tuning is in making sure you have appropriate
indexes.
However, note that the coursestudent.studentid column allows null so the
queries are not the same semantically. With not NOT IN query, no rows will
be returned if *any* null studentid exists in the coursestudent table. The
NOT EXIST query will return the stundents you expect.
If the coursestudent studentid column were changed to allow nulls, then both
NOT IN and NOT EXISTS queries will be semantically identical.
Hope this helps.
Dan Guzman
SQL Server MVP
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
> from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
> to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
> exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>|||You are absolutely correct. I meant to include the LEFT on the join.
Arnie Rowland, Ph.D.
Westwood Consulting, Inc
Most good judgment comes from experience.
Most experience comes from bad judgment.
- Anonymous
"Mikhail Berlyant" <remove-this-berlyant@.yahoo-inc.com> wrote in message
news:OzbZqbQ4GHA.3592@.TK2MSFTNGP05.phx.gbl...
> Arnie
> Please double-check - this shouldn't work
> There should be left join
> Mikhail Berlyant
> Eng.Manager
> Yahoo! Music
> "Arnie Rowland" <arnie@.1568.com> wrote in message
> news:ul7tQYQ4GHA.2144@.TK2MSFTNGP04.phx.gbl...
> To determine which is most efficient, you need to look at the execution
> plans, examine the I/O, and execution times.
> Here is an alternative:
> SELECT StudentID
> FROM Students s
> JOIN CourseStudent c
> ON s.StudentID = c.StudentID
> WHERE c.StudentID IS NULL
>
> --
> Arnie Rowland, Ph.D.
> Westwood Consulting, Inc
> Most good judgment comes from experience.
> Most experience comes from bad judgment.
> - Anonymous
>
> "Dodo Lurker" <none@.noemailplease> wrote in message
> news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> from
> to
> exist
>|||thank you everyone
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>
I have the following query
select studentid from students where studentid not in (select studentid from
coursestudent)
is there some way I could write this with using the 'not in'?
student is a table of students. coursestudent is a join table of courses to
students. I'm trying
to find those students who are not registered for a course. While the
above query works,
I'd like to find a more efficient query.
create table student
(studentid int identity primary key,
name varchar(50),
address1varchar(50),
address2 varchar(50),
city varchar(50),
state varchar(4),
zip varchar(11))
create table coursestudent
(courseid int
studentid int)
notes:
- non clustered index on courseid and non clustered index on studentid exist
- there is a foreign key relationship from coursestudent's studentid to
student studentidtry:
select a.studentid from students as a
left join coursestudent as b on a.studentid = b.studentid
where b.courseid is null
Mikhail Berlyant
Eng.Manager
Yahoo! Music
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>|||To determine which is most efficient, you need to look at the execution plan
s, examine the I/O, and execution times.
Here is an alternative:
SELECT StudentID
FROM Students s
JOIN CourseStudent c
ON s.StudentID = c.StudentID
WHERE c.StudentID IS NULL
--
Arnie Rowland, Ph.D.
Westwood Consulting, Inc
Most good judgment comes from experience.
Most experience comes from bad judgment.
- Anonymous
"Dodo Lurker" <none@.noemailplease> wrote in message news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.co
mcast.com...
> Hi
>
> I have the following query
>
> select studentid from students where studentid not in (select studentid fr
om
> coursestudent)
>
> is there some way I could write this with using the 'not in'?
>
> student is a table of students. coursestudent is a join table of courses
to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
>
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
>
> create table coursestudent
> (courseid int
> studentid int)
>
> notes:
> - non clustered index on courseid and non clustered index on studentid exi
st
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>
>
>|||Arnie
Please double-check - this shouldn't work
There should be left join
Mikhail Berlyant
Eng.Manager
Yahoo! Music
"Arnie Rowland" <arnie@.1568.com> wrote in message
news:ul7tQYQ4GHA.2144@.TK2MSFTNGP04.phx.gbl...
To determine which is most efficient, you need to look at the execution
plans, examine the I/O, and execution times.
Here is an alternative:
SELECT StudentID
FROM Students s
JOIN CourseStudent c
ON s.StudentID = c.StudentID
WHERE c.StudentID IS NULL
Arnie Rowland, Ph.D.
Westwood Consulting, Inc
Most good judgment comes from experience.
Most experience comes from bad judgment.
- Anonymous
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>|||Why do you think the solution you have is not efficient?
In the pubs database, these two queries have an almost identical plan, but
the wone with the NOT IN is slightly cheaper:
use pubs
select pub_name from publishers
where pub_id not in (select pub_id from titles)
select pub_name
from publishers p left join titles t
on p.pub_id = t.pub_id
where t.pub_id is null
HTH
Kalen Delaney, SQL Server MVP
http://sqlblog.com
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
> from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
> to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
> exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>|||> is there some way I could write this with using the 'not in'?
Another method is with NOT EXISTS. NOT IN and NOT EXISTS will both yield
identical execution plans (and performance) as long as the queries are
semantically the same. The SQL language is descriptive rather than
procedural so the optimizer will try to generate the most efficient plan
possible based on your query statement. As long as the expressions are
sargable, most performance tuning is in making sure you have appropriate
indexes.
However, note that the coursestudent.studentid column allows null so the
queries are not the same semantically. With not NOT IN query, no rows will
be returned if *any* null studentid exists in the coursestudent table. The
NOT EXIST query will return the stundents you expect.
If the coursestudent studentid column were changed to allow nulls, then both
NOT IN and NOT EXISTS queries will be semantically identical.
Hope this helps.
Dan Guzman
SQL Server MVP
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
> from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
> to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
> exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>|||You are absolutely correct. I meant to include the LEFT on the join.
Arnie Rowland, Ph.D.
Westwood Consulting, Inc
Most good judgment comes from experience.
Most experience comes from bad judgment.
- Anonymous
"Mikhail Berlyant" <remove-this-berlyant@.yahoo-inc.com> wrote in message
news:OzbZqbQ4GHA.3592@.TK2MSFTNGP05.phx.gbl...
> Arnie
> Please double-check - this shouldn't work
> There should be left join
> Mikhail Berlyant
> Eng.Manager
> Yahoo! Music
> "Arnie Rowland" <arnie@.1568.com> wrote in message
> news:ul7tQYQ4GHA.2144@.TK2MSFTNGP04.phx.gbl...
> To determine which is most efficient, you need to look at the execution
> plans, examine the I/O, and execution times.
> Here is an alternative:
> SELECT StudentID
> FROM Students s
> JOIN CourseStudent c
> ON s.StudentID = c.StudentID
> WHERE c.StudentID IS NULL
>
> --
> Arnie Rowland, Ph.D.
> Westwood Consulting, Inc
> Most good judgment comes from experience.
> Most experience comes from bad judgment.
> - Anonymous
>
> "Dodo Lurker" <none@.noemailplease> wrote in message
> news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> from
> to
> exist
>|||thank you everyone
"Dodo Lurker" <none@.noemailplease> wrote in message
news:nc-dndGE1OlQ6IXYnZ2dnUVZ_uudnZ2d@.comcast.com...
> Hi
> I have the following query
> select studentid from students where studentid not in (select studentid
from
> coursestudent)
> is there some way I could write this with using the 'not in'?
> student is a table of students. coursestudent is a join table of courses
to
> students. I'm trying
> to find those students who are not registered for a course. While the
> above query works,
> I'd like to find a more efficient query.
> create table student
> (studentid int identity primary key,
> name varchar(50),
> address1varchar(50),
> address2 varchar(50),
> city varchar(50),
> state varchar(4),
> zip varchar(11))
> create table coursestudent
> (courseid int
> studentid int)
> notes:
> - non clustered index on courseid and non clustered index on studentid
exist
> - there is a foreign key relationship from coursestudent's studentid to
> student studentid
>
>
Another Way To Write a Stored Procedure
In the stored procedure below, there are 9 different if conditions being
checked. I was wondering if there is a more efficient way (or not) to write
this procedure, without having to write the same select criteria each time.
The only thing different is the where clause. Any suggestions are greatly
appreciated.
SET QUOTED_IDENTIFIER ON
GO
SET ANSI_NULLS ON
GO
ALTER PROC ListParticipantsByRole(
@.testRoleEnum int,
@.errorID int = 0 OUTPUT)
AS
SET NOCOUNT ON
-- List Originators
IF (@.testRoleEnum = 1)
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE T.TestRoleOriginator = 1
ORDER BY P.DisplayName
-- List Validators
IF (@.testRoleEnum = 2)
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE T.TestRoleValidator = 1
ORDER BY P.DisplayName
-- List Screeners
IF (@.testRoleEnum = 3)
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE T.TestRoleScreener = 1
ORDER BY P.DisplayName
-- List SMEs
IF (@.testRoleEnum = 4)
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE T.TestRoleSME = 1
ORDER BY P.DisplayName
-- List Validation OPRs
IF (@.testRoleEnum = 5)
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE T.TestRoleValidationOPR = 1
ORDER BY P.DisplayName
-- List Validation Authorities
IF (@.testRoleEnum = 6)
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE T.TestRoleValidationAuthority = 1
ORDER BY P.DisplayName
-- List Officials
IF (@.testRoleEnum = 7)
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE T.TestRoleOfficial = 1
ORDER BY P.DisplayName
-- List Test Directors
IF (@.testRoleEnum = 8)
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE T.TestRoleTestDirector = 1
ORDER BY P.DisplayName
-- List Survey Participants
IF (@.testRoleEnum = 9)
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE T.TestRoleSurveyParticipant = 1
ORDER BY P.DisplayName
SET NOCOUNT OFF
GO
SET QUOTED_IDENTIFIER OFF
GO
SET ANSI_NULLS ON
GOSELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE 1 = CASE @.testRoleEnum
when 1 then T.TestRoleOriginator
when 2 then T.TestRoleValidator
...
end
ORDER BY P.DisplayName
"Mike Collins" <MikeCollins@.discussions.microsoft.com> wrote in message
news:C4C1B5B8-7E49-467A-83C7-4DEEED88B57B@.microsoft.com...
> In the stored procedure below, there are 9 different if conditions being
> checked. I was wondering if there is a more efficient way (or not) to
> write
> this procedure, without having to write the same select criteria each
> time.
> The only thing different is the where clause. Any suggestions are greatly
> appreciated.
> SET QUOTED_IDENTIFIER ON
> GO
> SET ANSI_NULLS ON
> GO
> ALTER PROC ListParticipantsByRole(
> @.testRoleEnum int,
> @.errorID int = 0 OUTPUT)
> AS
> SET NOCOUNT ON
> -- List Originators
> IF (@.testRoleEnum = 1)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleOriginator = 1
> ORDER BY P.DisplayName
> -- List Validators
> IF (@.testRoleEnum = 2)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidator = 1
> ORDER BY P.DisplayName
> -- List Screeners
> IF (@.testRoleEnum = 3)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleScreener = 1
> ORDER BY P.DisplayName
> -- List SMEs
> IF (@.testRoleEnum = 4)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleSME = 1
> ORDER BY P.DisplayName
> -- List Validation OPRs
> IF (@.testRoleEnum = 5)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidationOPR = 1
> ORDER BY P.DisplayName
> -- List Validation Authorities
> IF (@.testRoleEnum = 6)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidationAuthority = 1
> ORDER BY P.DisplayName
> -- List Officials
> IF (@.testRoleEnum = 7)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleOfficial = 1
> ORDER BY P.DisplayName
> -- List Test Directors
> IF (@.testRoleEnum = 8)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleTestDirector = 1
> ORDER BY P.DisplayName
> -- List Survey Participants
> IF (@.testRoleEnum = 9)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleSurveyParticipant = 1
> ORDER BY P.DisplayName
> SET NOCOUNT OFF
> GO
> SET QUOTED_IDENTIFIER OFF
> GO
> SET ANSI_NULLS ON
> GO
>|||Mike,
A redesign of TestParticipants is the best solution. Instead of
having a bunch of separate columns TestRoleThis, TestRoleThat,
TestRoleOther, ... you should have, depending on whether
a participant can have more than one role, either a column TestRole,
with possible values 'Validator', 'Screener', etc., or a separate table
TestParticipantRoles that links the participants with their roles.
Then your stored procedure becomes a single simple query like
this (case where there is a linking table):
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN TestParticipantRoles R ON T.PersonnelID = R.PersonnelId
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE R.RoleID = @.testRoleEnum
ORDER BY P.DisplayName
Short of that, you can still now do
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE CASE @.testRoleEnum
WHEN 1 THEN T.TestRoleOriginator
WHEN 2 THEN T.TestRoleValidator
..
END = 1
ORDER BY P.DisplayName
This latter solution may turn out to have poorer performance, however.
Steve Kass
Drew University
Mike Collins wrote:
>In the stored procedure below, there are 9 different if conditions being
>checked. I was wondering if there is a more efficient way (or not) to write
>this procedure, without having to write the same select criteria each time
.
>The only thing different is the where clause. Any suggestions are greatly
>appreciated.
>SET QUOTED_IDENTIFIER ON
>GO
>SET ANSI_NULLS ON
>GO
>ALTER PROC ListParticipantsByRole(
> @.testRoleEnum int,
> @.errorID int = 0 OUTPUT)
>AS
> SET NOCOUNT ON
> -- List Originators
> IF (@.testRoleEnum = 1)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleOriginator = 1
> ORDER BY P.DisplayName
> -- List Validators
> IF (@.testRoleEnum = 2)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidator = 1
> ORDER BY P.DisplayName
> -- List Screeners
> IF (@.testRoleEnum = 3)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleScreener = 1
> ORDER BY P.DisplayName
> -- List SMEs
> IF (@.testRoleEnum = 4)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleSME = 1
> ORDER BY P.DisplayName
> -- List Validation OPRs
> IF (@.testRoleEnum = 5)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidationOPR = 1
> ORDER BY P.DisplayName
> -- List Validation Authorities
> IF (@.testRoleEnum = 6)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidationAuthority = 1
> ORDER BY P.DisplayName
> -- List Officials
> IF (@.testRoleEnum = 7)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleOfficial = 1
> ORDER BY P.DisplayName
> -- List Test Directors
> IF (@.testRoleEnum = 8)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleTestDirector = 1
> ORDER BY P.DisplayName
> -- List Survey Participants
> IF (@.testRoleEnum = 9)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleSurveyParticipant = 1
> ORDER BY P.DisplayName
> SET NOCOUNT OFF
>GO
>SET QUOTED_IDENTIFIER OFF
>GO
>SET ANSI_NULLS ON
>GO
>
>|||Well, a more efficient design would store the numeric coefficient in a
single column, instead of having 9 different columns. It's hard to tell
from your requirements exactly what solution you need (e.g. can someone be a
screener and a roleSME?). But this is certainly not the best approach.
When you add or remove a role type, you have to change table structure and
all the code that references it. Blecch.
If a personnel member can only be in one role, then this design makes more
sense, IMHO:
CREATE TABLE dbo.TestRoles
(
TestRoleEnum INT PRIMARY KEY,
Description VARCHAR(32) UNIQUE
)
SET NOCOUNT ON;
INSERT dbo.TestRoles(Description) SELECT 'Originator';
...
CREATE TABLE dbo.TestParticipants
(
Personnelid INT /* FOREIGN KEY... */,
TestRoleEnum INT
)
Now your stored procedure can say:
ALTER PROCEDURE dbo.ListParticipantsByRole
@.testRoleEnum int,
@.errorID int = 0 OUTPUT
AS
BEGIN
SET NOCOUNT ON;
SELECT
P.DisplayName,
T.Personnelid
FROM
dbo.TestParticipants t
INNER JOIN
Common.dbo.vwPersonnelInfo p
ON
t.Personnelid = P.personellid
WHERE
t.TestRoleEnum = @.testRoleEnum
ORDER BY
P.DisplayName;
END
GO
And now you can add and remove test roles as you please, without having to
change any of the database structure. And as a bonus, your code becomes a
lot easier to read.
"Mike Collins" <MikeCollins@.discussions.microsoft.com> wrote in message
news:C4C1B5B8-7E49-467A-83C7-4DEEED88B57B@.microsoft.com...
> In the stored procedure below, there are 9 different if conditions being
> checked. I was wondering if there is a more efficient way (or not) to
> write
> this procedure, without having to write the same select criteria each
> time.
> The only thing different is the where clause. Any suggestions are greatly
> appreciated.
> SET QUOTED_IDENTIFIER ON
> GO
> SET ANSI_NULLS ON
> GO
> ALTER PROC ListParticipantsByRole(
> @.testRoleEnum int,
> @.errorID int = 0 OUTPUT)
> AS
> SET NOCOUNT ON
> -- List Originators
> IF (@.testRoleEnum = 1)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleOriginator = 1
> ORDER BY P.DisplayName
> -- List Validators
> IF (@.testRoleEnum = 2)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidator = 1
> ORDER BY P.DisplayName
> -- List Screeners
> IF (@.testRoleEnum = 3)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleScreener = 1
> ORDER BY P.DisplayName
> -- List SMEs
> IF (@.testRoleEnum = 4)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleSME = 1
> ORDER BY P.DisplayName
> -- List Validation OPRs
> IF (@.testRoleEnum = 5)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidationOPR = 1
> ORDER BY P.DisplayName
> -- List Validation Authorities
> IF (@.testRoleEnum = 6)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidationAuthority = 1
> ORDER BY P.DisplayName
> -- List Officials
> IF (@.testRoleEnum = 7)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleOfficial = 1
> ORDER BY P.DisplayName
> -- List Test Directors
> IF (@.testRoleEnum = 8)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleTestDirector = 1
> ORDER BY P.DisplayName
> -- List Survey Participants
> IF (@.testRoleEnum = 9)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleSurveyParticipant = 1
> ORDER BY P.DisplayName
> SET NOCOUNT OFF
> GO
> SET QUOTED_IDENTIFIER OFF
> GO
> SET ANSI_NULLS ON
> GO
>|||try this.. and see if it works faster...
writing for 2 ofthem.. u can add the rest..
Hope this helps.
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE @.testRoleEnum = 1 and T.TestRoleOriginator = 1
ORDER BY P.DisplayName
union all
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE @.testRoleEnum = 2 and T.TestRoleValidator = 1
ORDER BY P.DisplayName|||Thank you all for the quick and great responses. I see now better ways of
designing my tables and how to better write my stored procedure. In this
scenario, a person can have more than one role.
"Mike Collins" wrote:
> In the stored procedure below, there are 9 different if conditions being
> checked. I was wondering if there is a more efficient way (or not) to writ
e
> this procedure, without having to write the same select criteria each tim
e.
> The only thing different is the where clause. Any suggestions are greatly
> appreciated.
> SET QUOTED_IDENTIFIER ON
> GO
> SET ANSI_NULLS ON
> GO
> ALTER PROC ListParticipantsByRole(
> @.testRoleEnum int,
> @.errorID int = 0 OUTPUT)
> AS
> SET NOCOUNT ON
> -- List Originators
> IF (@.testRoleEnum = 1)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleOriginator = 1
> ORDER BY P.DisplayName
> -- List Validators
> IF (@.testRoleEnum = 2)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidator = 1
> ORDER BY P.DisplayName
> -- List Screeners
> IF (@.testRoleEnum = 3)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleScreener = 1
> ORDER BY P.DisplayName
> -- List SMEs
> IF (@.testRoleEnum = 4)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleSME = 1
> ORDER BY P.DisplayName
> -- List Validation OPRs
> IF (@.testRoleEnum = 5)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidationOPR = 1
> ORDER BY P.DisplayName
> -- List Validation Authorities
> IF (@.testRoleEnum = 6)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidationAuthority = 1
> ORDER BY P.DisplayName
> -- List Officials
> IF (@.testRoleEnum = 7)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleOfficial = 1
> ORDER BY P.DisplayName
> -- List Test Directors
> IF (@.testRoleEnum = 8)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleTestDirector = 1
> ORDER BY P.DisplayName
> -- List Survey Participants
> IF (@.testRoleEnum = 9)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleSurveyParticipant = 1
> ORDER BY P.DisplayName
> SET NOCOUNT OFF
> GO
> SET QUOTED_IDENTIFIER OFF
> GO
> SET ANSI_NULLS ON
> GO
>|||If you are planning to use a case statement, I would suggest going for a
union all
like I mentioned since it helps in better use of indexes, if any. If you
have not indexed the columns in the where clause, then go for the case. But
,
if you are redesining the table, thats the best way.|||That's a fairly straightforward approach. And here I was going to suggest
dynamic SQL.
Of course, the various suggestions to change the table structure are much
better in the long run.
"Raymond D'Anjou" <rdanjou@.canatradeNOSPAM.com> wrote in message
news:u9$RbXPeGHA.564@.TK2MSFTNGP02.phx.gbl...
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE 1 = CASE @.testRoleEnum
> when 1 then T.TestRoleOriginator
> when 2 then T.TestRoleValidator
> ...
> end
> ORDER BY P.DisplayName
> "Mike Collins" <MikeCollins@.discussions.microsoft.com> wrote in message
> news:C4C1B5B8-7E49-467A-83C7-4DEEED88B57B@.microsoft.com...
greatly
>|||"Jim Underwood" <james.underwoodATfallonclinic.com> wrote in message
news:O9EDeiPeGHA.3556@.TK2MSFTNGP02.phx.gbl...
> That's a fairly straightforward approach. And here I was going to suggest
> dynamic SQL.
> Of course, the various suggestions to change the table structure are much
> better in the long run.
I'm getting lazy. :-)|||Thanks for the additional input. Unfortunately it is not my decision to
redesign the database and I might have to use the case statements. I am
definitely going to give my two cents about redesigning the database.
"Omnibuzz" wrote:
> If you are planning to use a case statement, I would suggest going for a
> union all
> like I mentioned since it helps in better use of indexes, if any. If you
> have not indexed the columns in the where clause, then go for the case. Bu
t ,
> if you are redesining the table, thats the best way.sql
checked. I was wondering if there is a more efficient way (or not) to write
this procedure, without having to write the same select criteria each time.
The only thing different is the where clause. Any suggestions are greatly
appreciated.
SET QUOTED_IDENTIFIER ON
GO
SET ANSI_NULLS ON
GO
ALTER PROC ListParticipantsByRole(
@.testRoleEnum int,
@.errorID int = 0 OUTPUT)
AS
SET NOCOUNT ON
-- List Originators
IF (@.testRoleEnum = 1)
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE T.TestRoleOriginator = 1
ORDER BY P.DisplayName
-- List Validators
IF (@.testRoleEnum = 2)
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE T.TestRoleValidator = 1
ORDER BY P.DisplayName
-- List Screeners
IF (@.testRoleEnum = 3)
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE T.TestRoleScreener = 1
ORDER BY P.DisplayName
-- List SMEs
IF (@.testRoleEnum = 4)
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE T.TestRoleSME = 1
ORDER BY P.DisplayName
-- List Validation OPRs
IF (@.testRoleEnum = 5)
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE T.TestRoleValidationOPR = 1
ORDER BY P.DisplayName
-- List Validation Authorities
IF (@.testRoleEnum = 6)
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE T.TestRoleValidationAuthority = 1
ORDER BY P.DisplayName
-- List Officials
IF (@.testRoleEnum = 7)
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE T.TestRoleOfficial = 1
ORDER BY P.DisplayName
-- List Test Directors
IF (@.testRoleEnum = 8)
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE T.TestRoleTestDirector = 1
ORDER BY P.DisplayName
-- List Survey Participants
IF (@.testRoleEnum = 9)
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE T.TestRoleSurveyParticipant = 1
ORDER BY P.DisplayName
SET NOCOUNT OFF
GO
SET QUOTED_IDENTIFIER OFF
GO
SET ANSI_NULLS ON
GOSELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE 1 = CASE @.testRoleEnum
when 1 then T.TestRoleOriginator
when 2 then T.TestRoleValidator
...
end
ORDER BY P.DisplayName
"Mike Collins" <MikeCollins@.discussions.microsoft.com> wrote in message
news:C4C1B5B8-7E49-467A-83C7-4DEEED88B57B@.microsoft.com...
> In the stored procedure below, there are 9 different if conditions being
> checked. I was wondering if there is a more efficient way (or not) to
> write
> this procedure, without having to write the same select criteria each
> time.
> The only thing different is the where clause. Any suggestions are greatly
> appreciated.
> SET QUOTED_IDENTIFIER ON
> GO
> SET ANSI_NULLS ON
> GO
> ALTER PROC ListParticipantsByRole(
> @.testRoleEnum int,
> @.errorID int = 0 OUTPUT)
> AS
> SET NOCOUNT ON
> -- List Originators
> IF (@.testRoleEnum = 1)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleOriginator = 1
> ORDER BY P.DisplayName
> -- List Validators
> IF (@.testRoleEnum = 2)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidator = 1
> ORDER BY P.DisplayName
> -- List Screeners
> IF (@.testRoleEnum = 3)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleScreener = 1
> ORDER BY P.DisplayName
> -- List SMEs
> IF (@.testRoleEnum = 4)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleSME = 1
> ORDER BY P.DisplayName
> -- List Validation OPRs
> IF (@.testRoleEnum = 5)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidationOPR = 1
> ORDER BY P.DisplayName
> -- List Validation Authorities
> IF (@.testRoleEnum = 6)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidationAuthority = 1
> ORDER BY P.DisplayName
> -- List Officials
> IF (@.testRoleEnum = 7)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleOfficial = 1
> ORDER BY P.DisplayName
> -- List Test Directors
> IF (@.testRoleEnum = 8)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleTestDirector = 1
> ORDER BY P.DisplayName
> -- List Survey Participants
> IF (@.testRoleEnum = 9)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleSurveyParticipant = 1
> ORDER BY P.DisplayName
> SET NOCOUNT OFF
> GO
> SET QUOTED_IDENTIFIER OFF
> GO
> SET ANSI_NULLS ON
> GO
>|||Mike,
A redesign of TestParticipants is the best solution. Instead of
having a bunch of separate columns TestRoleThis, TestRoleThat,
TestRoleOther, ... you should have, depending on whether
a participant can have more than one role, either a column TestRole,
with possible values 'Validator', 'Screener', etc., or a separate table
TestParticipantRoles that links the participants with their roles.
Then your stored procedure becomes a single simple query like
this (case where there is a linking table):
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN TestParticipantRoles R ON T.PersonnelID = R.PersonnelId
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE R.RoleID = @.testRoleEnum
ORDER BY P.DisplayName
Short of that, you can still now do
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE CASE @.testRoleEnum
WHEN 1 THEN T.TestRoleOriginator
WHEN 2 THEN T.TestRoleValidator
..
END = 1
ORDER BY P.DisplayName
This latter solution may turn out to have poorer performance, however.
Steve Kass
Drew University
Mike Collins wrote:
>In the stored procedure below, there are 9 different if conditions being
>checked. I was wondering if there is a more efficient way (or not) to write
>this procedure, without having to write the same select criteria each time
.
>The only thing different is the where clause. Any suggestions are greatly
>appreciated.
>SET QUOTED_IDENTIFIER ON
>GO
>SET ANSI_NULLS ON
>GO
>ALTER PROC ListParticipantsByRole(
> @.testRoleEnum int,
> @.errorID int = 0 OUTPUT)
>AS
> SET NOCOUNT ON
> -- List Originators
> IF (@.testRoleEnum = 1)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleOriginator = 1
> ORDER BY P.DisplayName
> -- List Validators
> IF (@.testRoleEnum = 2)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidator = 1
> ORDER BY P.DisplayName
> -- List Screeners
> IF (@.testRoleEnum = 3)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleScreener = 1
> ORDER BY P.DisplayName
> -- List SMEs
> IF (@.testRoleEnum = 4)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleSME = 1
> ORDER BY P.DisplayName
> -- List Validation OPRs
> IF (@.testRoleEnum = 5)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidationOPR = 1
> ORDER BY P.DisplayName
> -- List Validation Authorities
> IF (@.testRoleEnum = 6)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidationAuthority = 1
> ORDER BY P.DisplayName
> -- List Officials
> IF (@.testRoleEnum = 7)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleOfficial = 1
> ORDER BY P.DisplayName
> -- List Test Directors
> IF (@.testRoleEnum = 8)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleTestDirector = 1
> ORDER BY P.DisplayName
> -- List Survey Participants
> IF (@.testRoleEnum = 9)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleSurveyParticipant = 1
> ORDER BY P.DisplayName
> SET NOCOUNT OFF
>GO
>SET QUOTED_IDENTIFIER OFF
>GO
>SET ANSI_NULLS ON
>GO
>
>|||Well, a more efficient design would store the numeric coefficient in a
single column, instead of having 9 different columns. It's hard to tell
from your requirements exactly what solution you need (e.g. can someone be a
screener and a roleSME?). But this is certainly not the best approach.
When you add or remove a role type, you have to change table structure and
all the code that references it. Blecch.
If a personnel member can only be in one role, then this design makes more
sense, IMHO:
CREATE TABLE dbo.TestRoles
(
TestRoleEnum INT PRIMARY KEY,
Description VARCHAR(32) UNIQUE
)
SET NOCOUNT ON;
INSERT dbo.TestRoles(Description) SELECT 'Originator';
...
CREATE TABLE dbo.TestParticipants
(
Personnelid INT /* FOREIGN KEY... */,
TestRoleEnum INT
)
Now your stored procedure can say:
ALTER PROCEDURE dbo.ListParticipantsByRole
@.testRoleEnum int,
@.errorID int = 0 OUTPUT
AS
BEGIN
SET NOCOUNT ON;
SELECT
P.DisplayName,
T.Personnelid
FROM
dbo.TestParticipants t
INNER JOIN
Common.dbo.vwPersonnelInfo p
ON
t.Personnelid = P.personellid
WHERE
t.TestRoleEnum = @.testRoleEnum
ORDER BY
P.DisplayName;
END
GO
And now you can add and remove test roles as you please, without having to
change any of the database structure. And as a bonus, your code becomes a
lot easier to read.
"Mike Collins" <MikeCollins@.discussions.microsoft.com> wrote in message
news:C4C1B5B8-7E49-467A-83C7-4DEEED88B57B@.microsoft.com...
> In the stored procedure below, there are 9 different if conditions being
> checked. I was wondering if there is a more efficient way (or not) to
> write
> this procedure, without having to write the same select criteria each
> time.
> The only thing different is the where clause. Any suggestions are greatly
> appreciated.
> SET QUOTED_IDENTIFIER ON
> GO
> SET ANSI_NULLS ON
> GO
> ALTER PROC ListParticipantsByRole(
> @.testRoleEnum int,
> @.errorID int = 0 OUTPUT)
> AS
> SET NOCOUNT ON
> -- List Originators
> IF (@.testRoleEnum = 1)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleOriginator = 1
> ORDER BY P.DisplayName
> -- List Validators
> IF (@.testRoleEnum = 2)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidator = 1
> ORDER BY P.DisplayName
> -- List Screeners
> IF (@.testRoleEnum = 3)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleScreener = 1
> ORDER BY P.DisplayName
> -- List SMEs
> IF (@.testRoleEnum = 4)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleSME = 1
> ORDER BY P.DisplayName
> -- List Validation OPRs
> IF (@.testRoleEnum = 5)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidationOPR = 1
> ORDER BY P.DisplayName
> -- List Validation Authorities
> IF (@.testRoleEnum = 6)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidationAuthority = 1
> ORDER BY P.DisplayName
> -- List Officials
> IF (@.testRoleEnum = 7)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleOfficial = 1
> ORDER BY P.DisplayName
> -- List Test Directors
> IF (@.testRoleEnum = 8)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleTestDirector = 1
> ORDER BY P.DisplayName
> -- List Survey Participants
> IF (@.testRoleEnum = 9)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleSurveyParticipant = 1
> ORDER BY P.DisplayName
> SET NOCOUNT OFF
> GO
> SET QUOTED_IDENTIFIER OFF
> GO
> SET ANSI_NULLS ON
> GO
>|||try this.. and see if it works faster...
writing for 2 ofthem.. u can add the rest..
Hope this helps.
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE @.testRoleEnum = 1 and T.TestRoleOriginator = 1
ORDER BY P.DisplayName
union all
SELECT P.DisplayName, T.PersonnelID
FROM TestParticipants T
JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
WHERE @.testRoleEnum = 2 and T.TestRoleValidator = 1
ORDER BY P.DisplayName|||Thank you all for the quick and great responses. I see now better ways of
designing my tables and how to better write my stored procedure. In this
scenario, a person can have more than one role.
"Mike Collins" wrote:
> In the stored procedure below, there are 9 different if conditions being
> checked. I was wondering if there is a more efficient way (or not) to writ
e
> this procedure, without having to write the same select criteria each tim
e.
> The only thing different is the where clause. Any suggestions are greatly
> appreciated.
> SET QUOTED_IDENTIFIER ON
> GO
> SET ANSI_NULLS ON
> GO
> ALTER PROC ListParticipantsByRole(
> @.testRoleEnum int,
> @.errorID int = 0 OUTPUT)
> AS
> SET NOCOUNT ON
> -- List Originators
> IF (@.testRoleEnum = 1)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleOriginator = 1
> ORDER BY P.DisplayName
> -- List Validators
> IF (@.testRoleEnum = 2)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidator = 1
> ORDER BY P.DisplayName
> -- List Screeners
> IF (@.testRoleEnum = 3)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleScreener = 1
> ORDER BY P.DisplayName
> -- List SMEs
> IF (@.testRoleEnum = 4)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleSME = 1
> ORDER BY P.DisplayName
> -- List Validation OPRs
> IF (@.testRoleEnum = 5)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidationOPR = 1
> ORDER BY P.DisplayName
> -- List Validation Authorities
> IF (@.testRoleEnum = 6)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleValidationAuthority = 1
> ORDER BY P.DisplayName
> -- List Officials
> IF (@.testRoleEnum = 7)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleOfficial = 1
> ORDER BY P.DisplayName
> -- List Test Directors
> IF (@.testRoleEnum = 8)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleTestDirector = 1
> ORDER BY P.DisplayName
> -- List Survey Participants
> IF (@.testRoleEnum = 9)
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE T.TestRoleSurveyParticipant = 1
> ORDER BY P.DisplayName
> SET NOCOUNT OFF
> GO
> SET QUOTED_IDENTIFIER OFF
> GO
> SET ANSI_NULLS ON
> GO
>|||If you are planning to use a case statement, I would suggest going for a
union all
like I mentioned since it helps in better use of indexes, if any. If you
have not indexed the columns in the where clause, then go for the case. But
,
if you are redesining the table, thats the best way.|||That's a fairly straightforward approach. And here I was going to suggest
dynamic SQL.
Of course, the various suggestions to change the table structure are much
better in the long run.
"Raymond D'Anjou" <rdanjou@.canatradeNOSPAM.com> wrote in message
news:u9$RbXPeGHA.564@.TK2MSFTNGP02.phx.gbl...
> SELECT P.DisplayName, T.PersonnelID
> FROM TestParticipants T
> JOIN Common..vwPersonnelInfo P ON T.PersonnelID = P.PersonnelId
> WHERE 1 = CASE @.testRoleEnum
> when 1 then T.TestRoleOriginator
> when 2 then T.TestRoleValidator
> ...
> end
> ORDER BY P.DisplayName
> "Mike Collins" <MikeCollins@.discussions.microsoft.com> wrote in message
> news:C4C1B5B8-7E49-467A-83C7-4DEEED88B57B@.microsoft.com...
greatly
>|||"Jim Underwood" <james.underwoodATfallonclinic.com> wrote in message
news:O9EDeiPeGHA.3556@.TK2MSFTNGP02.phx.gbl...
> That's a fairly straightforward approach. And here I was going to suggest
> dynamic SQL.
> Of course, the various suggestions to change the table structure are much
> better in the long run.
I'm getting lazy. :-)|||Thanks for the additional input. Unfortunately it is not my decision to
redesign the database and I might have to use the case statements. I am
definitely going to give my two cents about redesigning the database.
"Omnibuzz" wrote:
> If you are planning to use a case statement, I would suggest going for a
> union all
> like I mentioned since it helps in better use of indexes, if any. If you
> have not indexed the columns in the where clause, then go for the case. Bu
t ,
> if you are redesining the table, thats the best way.sql
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