How to simplify/optimize this query?

Hi,
Could the following query be simplified/optimized? The database has a table
that maps users to locations, locations to chapters, and sections to
chapters. I need to issue a query that would return a list of sections that
can be assigned to a user (excluding the ones that have already been
assigned) .
@.UserId int
[...]
SELECT SectionID, [Name],
FROM Section
WHERE SectionID NOT IN (SELECT SectionID FROM UserSection WHERE UserID = @.UserID) AND
SectionID IN (SELECT DISTINCT SectionID FROM ChapterSection
WHERE ChapterID IN
(SELECT DISTINCT ChapterID FROM ChapterLocation
WHERE LocationID IN
(SELECT LocationID FROM UserLocation WHERE UserID = @.UserID)
)
);
I realize that this might not be as clear as it should be but I'd appreciate
_any_ suggestions.
Thanks,
Dan> Could the following query be simplified/optimized?
I think the query below is equivalent. I think indexes on the columns in
the WHERE/JOIN clauses may help performance(e.g. a composite index on
UserSection UserID, SectionID).
SELECT SectionID, [Name]
FROM dbo.Section s
WHERE
NOT EXISTS(
SELECT * FROM dbo.UserSection us
WHERE
us.SectionID = s.SectionID
AND UserID = @.UserID
) AND
EXISTS(
SELECT * FROM dbo.ChapterSection cs
JOIN dbo.ChapterLocation cl ON
cl.ChapterID = cs.ChapterID
JOIN dbo.UserLocation ul ON
ul.LocationID = cl.LocationID
AND UserID = @.UserID)
--
Hope this helps.
Dan Guzman
SQL Server MVP
http://weblogs.sqlteam.com/dang/
"dan" <dan@.company.com> wrote in message
news:uVUBR7mqIHA.3804@.TK2MSFTNGP02.phx.gbl...
> Hi,
> Could the following query be simplified/optimized? The database has a
> table that maps users to locations, locations to chapters, and sections to
> chapters. I need to issue a query that would return a list of sections
> that can be assigned to a user (excluding the ones that have already been
> assigned) .
> @.UserId int
> [...]
> SELECT SectionID, [Name],
> FROM Section
> WHERE SectionID NOT IN (SELECT SectionID FROM UserSection WHERE UserID => @.UserID) AND
> SectionID IN (SELECT DISTINCT SectionID FROM ChapterSection
> WHERE ChapterID IN
> (SELECT DISTINCT ChapterID FROM ChapterLocation
> WHERE LocationID IN
> (SELECT LocationID FROM UserLocation WHERE UserID = @.UserID)
> )
> );
> I realize that this might not be as clear as it should be but I'd
> appreciate _any_ suggestions.
> Thanks,
> Dan
>|||Thanks for the reply. The query looks clean but there seems to be a problem
with EXISTS() in the WHERE clause. Some of the sections included in the
result set are not assigned to the user's location(s) (implicitly through
chapters). I.e. the query selects chapters that are not assigned to user's
locations in addition to the chapters that are assigned.
Any suggestions?
Thanks,
Dan
"Dan Guzman" <guzmanda@.nospam-online.sbcglobal.net> wrote in message
news:A400C6C3-53B6-4A01-B0DD-182ACF421236@.microsoft.com...
>> Could the following query be simplified/optimized?
> I think the query below is equivalent. I think indexes on the columns in
> the WHERE/JOIN clauses may help performance(e.g. a composite index on
> UserSection UserID, SectionID).
> SELECT SectionID, [Name]
> FROM dbo.Section s
> WHERE
> NOT EXISTS(
> SELECT * FROM dbo.UserSection us
> WHERE
> us.SectionID = s.SectionID
> AND UserID = @.UserID
> ) AND
> EXISTS(
> SELECT * FROM dbo.ChapterSection cs
> JOIN dbo.ChapterLocation cl ON
> cl.ChapterID = cs.ChapterID
> JOIN dbo.UserLocation ul ON
> ul.LocationID = cl.LocationID
> AND UserID = @.UserID)
> --
> Hope this helps.
> Dan Guzman
> SQL Server MVP
> http://weblogs.sqlteam.com/dang/
> "dan" <dan@.company.com> wrote in message
> news:uVUBR7mqIHA.3804@.TK2MSFTNGP02.phx.gbl...
>> Hi,
>> Could the following query be simplified/optimized? The database has a
>> table that maps users to locations, locations to chapters, and sections
>> to chapters. I need to issue a query that would return a list of sections
>> that can be assigned to a user (excluding the ones that have already been
>> assigned) .
>> @.UserId int
>> [...]
>> SELECT SectionID, [Name],
>> FROM Section
>> WHERE SectionID NOT IN (SELECT SectionID FROM UserSection WHERE UserID =>> @.UserID) AND
>> SectionID IN (SELECT DISTINCT SectionID FROM ChapterSection
>> WHERE ChapterID IN
>> (SELECT DISTINCT ChapterID FROM ChapterLocation
>> WHERE LocationID IN
>> (SELECT LocationID FROM UserLocation WHERE UserID = @.UserID)
>> )
>> );
>> I realize that this might not be as clear as it should be but I'd
>> appreciate _any_ suggestions.
>> Thanks,
>> Dan
>>
>|||> Thanks for the reply. The query looks clean but there seems to be a
> problem
> with EXISTS() in the WHERE clause. Some of the sections included in the
> result set are not assigned to the user's location(s) (implicitly through
> chapters). I.e. the query selects chapters that are not assigned to
> user's locations in addition to the chapters that are assigned.
> Any suggestions?
I missed the join from ChapterSection.SectionID back to Section.SectionID.
See the corrected query below. If this still doesn't work for you, please
post the table DDL and sample data so that I can test the solution.
SELECT SectionID, [Name]
FROM dbo.Section s
WHERE
NOT EXISTS(
SELECT * FROM dbo.UserSection us
WHERE
us.SectionID = s.SectionID
AND UserID = @.UserID
)
AND EXISTS(
SELECT * FROM dbo.ChapterSection cs
JOIN dbo.ChapterLocation cl ON
cl.ChapterID = cs.ChapterID
JOIN dbo.UserLocation ul ON
ul.LocationID = cl.LocationID
AND UserID = @.UserID
AND cs.SectionID = s.SectionID
)
--
Hope this helps.
Dan Guzman
SQL Server MVP
http://weblogs.sqlteam.com/dang/
"dan" <dan@.company.com> wrote in message
news:eB2qg%23sqIHA.2492@.TK2MSFTNGP06.phx.gbl...
> Thanks for the reply. The query looks clean but there seems to be a
> problem with EXISTS() in the WHERE clause. Some of the sections included
> in the result set are not assigned to the user's location(s) (implicitly
> through chapters). I.e. the query selects chapters that are not assigned
> to user's locations in addition to the chapters that are assigned.
> Any suggestions?
> Thanks,
> Dan
> "Dan Guzman" <guzmanda@.nospam-online.sbcglobal.net> wrote in message
> news:A400C6C3-53B6-4A01-B0DD-182ACF421236@.microsoft.com...
>> Could the following query be simplified/optimized?
>> I think the query below is equivalent. I think indexes on the columns in
>> the WHERE/JOIN clauses may help performance(e.g. a composite index on
>> UserSection UserID, SectionID).
>> SELECT SectionID, [Name]
>> FROM dbo.Section s
>> WHERE
>> NOT EXISTS(
>> SELECT * FROM dbo.UserSection us
>> WHERE
>> us.SectionID = s.SectionID
>> AND UserID = @.UserID
>> ) AND
>> EXISTS(
>> SELECT * FROM dbo.ChapterSection cs
>> JOIN dbo.ChapterLocation cl ON
>> cl.ChapterID = cs.ChapterID
>> JOIN dbo.UserLocation ul ON
>> ul.LocationID = cl.LocationID
>> AND UserID = @.UserID)
>> --
>> Hope this helps.
>> Dan Guzman
>> SQL Server MVP
>> http://weblogs.sqlteam.com/dang/
>> "dan" <dan@.company.com> wrote in message
>> news:uVUBR7mqIHA.3804@.TK2MSFTNGP02.phx.gbl...
>> Hi,
>> Could the following query be simplified/optimized? The database has a
>> table that maps users to locations, locations to chapters, and sections
>> to chapters. I need to issue a query that would return a list of
>> sections that can be assigned to a user (excluding the ones that have
>> already been assigned) .
>> @.UserId int
>> [...]
>> SELECT SectionID, [Name],
>> FROM Section
>> WHERE SectionID NOT IN (SELECT SectionID FROM UserSection WHERE UserID =>> @.UserID) AND
>> SectionID IN (SELECT DISTINCT SectionID FROM ChapterSection
>> WHERE ChapterID IN
>> (SELECT DISTINCT ChapterID FROM ChapterLocation
>> WHERE LocationID IN
>> (SELECT LocationID FROM UserLocation WHERE UserID = @.UserID)
>> )
>> );
>> I realize that this might not be as clear as it should be but I'd
>> appreciate _any_ suggestions.
>> Thanks,
>> Dan
>>
>|||Thanks. It works now.
"Dan Guzman" <guzmanda@.nospam-online.sbcglobal.net> wrote in message
news:5F09A613-CEF3-45CA-B2EA-6A3D39CB69D5@.microsoft.com...
>> Thanks for the reply. The query looks clean but there seems to be a
>> problem
>> with EXISTS() in the WHERE clause. Some of the sections included in the
>> result set are not assigned to the user's location(s) (implicitly through
>> chapters). I.e. the query selects chapters that are not assigned to
>> user's locations in addition to the chapters that are assigned.
>> Any suggestions?
> I missed the join from ChapterSection.SectionID back to Section.SectionID.
> See the corrected query below. If this still doesn't work for you, please
> post the table DDL and sample data so that I can test the solution.
> SELECT SectionID, [Name]
> FROM dbo.Section s
> WHERE
> NOT EXISTS(
> SELECT * FROM dbo.UserSection us
> WHERE
> us.SectionID = s.SectionID
> AND UserID = @.UserID
> )
> AND EXISTS(
> SELECT * FROM dbo.ChapterSection cs
> JOIN dbo.ChapterLocation cl ON
> cl.ChapterID = cs.ChapterID
> JOIN dbo.UserLocation ul ON
> ul.LocationID = cl.LocationID
> AND UserID = @.UserID
> AND cs.SectionID = s.SectionID
> )
> --
> Hope this helps.
> Dan Guzman
> SQL Server MVP
> http://weblogs.sqlteam.com/dang/
> "dan" <dan@.company.com> wrote in message
> news:eB2qg%23sqIHA.2492@.TK2MSFTNGP06.phx.gbl...
>> Thanks for the reply. The query looks clean but there seems to be a
>> problem with EXISTS() in the WHERE clause. Some of the sections included
>> in the result set are not assigned to the user's location(s) (implicitly
>> through chapters). I.e. the query selects chapters that are not assigned
>> to user's locations in addition to the chapters that are assigned.
>> Any suggestions?
>> Thanks,
>> Dan
>> "Dan Guzman" <guzmanda@.nospam-online.sbcglobal.net> wrote in message
>> news:A400C6C3-53B6-4A01-B0DD-182ACF421236@.microsoft.com...
>> Could the following query be simplified/optimized?
>> I think the query below is equivalent. I think indexes on the columns
>> in the WHERE/JOIN clauses may help performance(e.g. a composite index on
>> UserSection UserID, SectionID).
>> SELECT SectionID, [Name]
>> FROM dbo.Section s
>> WHERE
>> NOT EXISTS(
>> SELECT * FROM dbo.UserSection us
>> WHERE
>> us.SectionID = s.SectionID
>> AND UserID = @.UserID
>> ) AND
>> EXISTS(
>> SELECT * FROM dbo.ChapterSection cs
>> JOIN dbo.ChapterLocation cl ON
>> cl.ChapterID = cs.ChapterID
>> JOIN dbo.UserLocation ul ON
>> ul.LocationID = cl.LocationID
>> AND UserID = @.UserID)
>> --
>> Hope this helps.
>> Dan Guzman
>> SQL Server MVP
>> http://weblogs.sqlteam.com/dang/
>> "dan" <dan@.company.com> wrote in message
>> news:uVUBR7mqIHA.3804@.TK2MSFTNGP02.phx.gbl...
>> Hi,
>> Could the following query be simplified/optimized? The database has a
>> table that maps users to locations, locations to chapters, and sections
>> to chapters. I need to issue a query that would return a list of
>> sections that can be assigned to a user (excluding the ones that have
>> already been assigned) .
>> @.UserId int
>> [...]
>> SELECT SectionID, [Name],
>> FROM Section
>> WHERE SectionID NOT IN (SELECT SectionID FROM UserSection WHERE UserID
>> = @.UserID) AND
>> SectionID IN (SELECT DISTINCT SectionID FROM ChapterSection
>> WHERE ChapterID IN
>> (SELECT DISTINCT ChapterID FROM ChapterLocation
>> WHERE LocationID IN
>> (SELECT LocationID FROM UserLocation WHERE UserID =>> @.UserID)
>> )
>> );
>> I realize that this might not be as clear as it should be but I'd
>> appreciate _any_ suggestions.
>> Thanks,
>> Dan
>>
>>
>