IN operator

• Dung Dinh

  SSCrazy

  Points: 2513

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  November 15, 2012 at 9:47 pm

  #267053

  Hi all,

  While reading an article from http://www.sql-server-performance.com. They said "The Query Optimizer converts the Transact-SQL IN clause to the OR operator when parsing your code". Is is correct?

• Randy Knight

  SSC-Addicted

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  November 15, 2012 at 9:57 pm

  #1559613

  Write your query both ways and look at the execution plan.

  It is best to use articles and/or advice on forums as guidance to figure things out and confirm stuff for yourself.

• Gail Shaw

  SSC Guru

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  November 16, 2012 at 1:53 am

  #1559678

  Providing it's IN with a list of values, yes. Trivial to prove, just look at the seek predicate/predicate on the index seek/scan in the exec plan

  Gail Shaw
  Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
  SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

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