Microsoft KB Archive/173314

= BUG: IN Subquery Reformats and Is Slower Than an Equivalent Join =

Article ID: 173314

Article Last Modified on 10/16/2003

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APPLIES TO


 * Microsoft SQL Server 6.5 Standard Edition
 * Microsoft SQL Server 6.0 Standard Edition

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This article was previously published under Q173314



SYMPTOMS
BUG #: 17227 (6.5)

A join combined with an IN subquery may cause a reformat access plan and be much slower than the logically equivalent pure join query. In general, an IN subquery should have approximately the same performance as the equivalent join.



WORKAROUND
Express the IN subquery as join, or break it down to several smaller queries using temporary tables, which collectively produce the same result.



STATUS
Microsoft has confirmed this to be a problem in Microsoft SQL Server versions 6.0 and 6.5. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

Additional query words: sub

Keywords: kbbug kbusage KB173314

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