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plurals

POJoining on varchar(50) foreign key slows query
primarykey
Id
603845
data
AcceptedAnswerId
603878
AnswerCount
4
ClosedDate
CommentCount
9
CommunityOwnedDate
CreationDate
2009-03-02T20:21:05.060
FavoriteCount
0
LastActivityDate
2009-03-06T21:04:53.753
LastEditDate
2009-03-06T21:04:53.753
LastEditorUserId
67407
OwnerUserId
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PostTypeId
1
Score
1
ViewCount
1237
LastEditorDisplayName
coldice
text
Body
I have this query which is pretty long, but adding a where clause to it, or joining on a string makes it take an extra 2 seconds to run. I can't figure out why. Here's the query in full: <pre><code>ALTER PROCEDURE [dbo].[RespondersByPracticeID] @practiceID int = null, @activeOnly bit = 1 AS BEGIN SET NOCOUNT ON; select isnull(sum(isResponder),0) as [Responders] ,isnull(count(*) - sum(isResponder),0) as [NonResponders] ,isnull((select count(p.patientID) from patient p inner join practice on practice.practiceid = p.practiceid inner join [lookup] l on p.dosing = l.lookupid and l.lookupid = 'da_ncd' where p.practiceID = isnull(@practiceID, p.practiceID) and p.active = case @activeOnly when 1 then 1 else p.active end ) - (isnull(sum(isResponder),0) + isnull(count(*) - sum(isResponder),0)),0) as [Undetermined] from ( select v.patientID ,firstVisit.hbLevel as startHb ,maxHbVisit.hblevel as maxHb , case when (maxHbVisit.hblevel - firstVisit.hbLevel >= 1) then 1 else 0 end as isResponder ,count(v.patientID) as patientCount from patient p inner join visit v on v.patientid = v.patientid inner join practice on practice.practiceid = p.practiceid inner join [lookup] l on p.dosing = l.lookupid and l.lookupid = 'da_ncd' inner join ( SELECT p.PatientID ,v.VisitID ,v.hblevel ,v.VisitDate FROM Patient p INNER JOIN Visit v ON p.PatientID = v.PatientID WHERE v.VisitDate = ( SELECT MIN(VisitDate) FROM Visit WHERE PatientId = p.PatientId ) ) firstVisit on firstVisit.patientID = v.patientID inner join ( select p.patientID ,max(v.hbLevel) as hblevel from Patient p INNER JOIN Visit v ON p.PatientID = v.PatientID group by p.patientID ) MaxHbVisit on maxHbVisit.patientid = v.patientId where p.practiceID = isnull(@practiceID, p.practiceID) and p.active = case @activeOnly when 1 then 1 else p.active end group by v.patientID ,firstVisit.hbLevel ,maxHbVisit.hblevel having datediff( d, dateadd( day ,-DatePart( dw ,min(v.visitDate) ) + 1 ,min(v.visitDate) ) , max(v.visitDate) ) >= (7 * 8) -- Eight weeks. ) responders END </code></pre> The line that slows it down is: <pre><code>inner join [lookup] l on p.dosing = l.lookupid and l.lookupid = 'da_ncd' </code></pre> Also, moving it to the <code>where</code> clause has the same effect: <pre><code>where p.dosing = 'da_ncd' </code></pre> Otherwise, the query runs almost instantly. <code>>.<</code>
Tags
<database><tsql><optimization>
Title
Joining on varchar(50) foreign key slows query
singulars
PostAcceptedAnswerId
1. PO
 singulars
 PostTypePostTypeId
 PTAnswer
PostParentId
1. This table or related slice is empty.
PostTypePostTypeId
1. PTQuestion
UserLastEditorUserId
1. USMax Gontar
UserOwnerUserId
1. USShawn
plurals
PostLinksPostIdRelatedPostId
1. This table or related slice is empty.
PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. This table or related slice is empty.
PostsParentIdCreationDate
1. PO
 singulars
 PostTypePostTypeId
 PTAnswer
2. PO
 singulars
 PostTypePostTypeId
 PTAnswer
3. PO
 singulars
 PostTypePostTypeId
 PTAnswer
VotesPostIdCreationDate
1. VO
 singulars
 PostPostId
 POJoining on varchar(50) foreign key slows query
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTUpMod
CommentsPostId

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