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Suggested Indexes on a SQL 2000 DB - Preventing Bookmark Lookups

开发者 https://www.devze.com 2023-02-15 21:40 出处:网络
So I have the following code - written by a 3rd party supplier. Can anyone suggest what indexes should be used to prevent bookmark lookups? Do you need the content of the UDFs as well?

So I have the following code - written by a 3rd party supplier. Can anyone suggest what indexes should be used to prevent bookmark lookups? Do you need the content of the UDFs as well?

SELECT reportTbl.ReportDBID, 
case when reportTbl.ResultStatus = 'P' then 'PRELIMINARY'  
when reportTbl.ResultStatus = 'I' then 'INTERIM' 
else reportTbl.ResultStatus end   As Status, 1   as isAccessible, 
dbo.repAb(reportTbl.ReportDBID)   As Abnormality, 
dbo.repAb(reportTbl.ReportDBID)   As Importance,   
reportTbl.UniversalServiceDescription as Title,  
reportTbl.DiagnosticServSectID as ServiceDescription, 
case when ResultStatus='X' then 'Cancelled'   when ResultStatus='C' OR dbo.inferStatus(reportTbl.ReportDBID) = 'C' then 'Amended' 
else reportTbl.DiagnosticServSectID   end AS subCategory, 
reportTbl.DiagnosticServSectID as subCategoryAlt,  
case when cdrOth.FamilyName is not null   then cdrOth.FamilyName else cdrOth.IDNumber end As Autho开发者_Python百科r, 
reportTbl.ObservationDateTime 
FROM reportTbl WITH (NOLOCK)
INNER JOIN patientTbl WITH (NOLOCK) ON reportTbl.patID = patientTbl.patID
LEFT OUTER JOIN cdrOth WITH (NOLOCK) ON reportTbl.ordID = cdrOth.SegCrossReferenceDBID 
WHERE
patientTbl.recNumber ='111111111'
and reportTbl.ResultStatus IN ('G', 'H','I', 'J')
and reportTbl.DiagnosticServSectID IN ('E', 'F')
and reportTbl.UniversalServiceCode NOT IN  ('A', 'B', 'C', 'D') -- there are roughly 750 options so using NOT IN is easier
ORDER BY ReportDBID


Bookmark lookups are usually removed by using covering indexes

Some great examples here

This explains it better than I would. But the summary is that columns in the bookmark lookup should be added to the index.

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