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Index on a Column with NULLs

  • May 11, 2013 at 6:39 am

    #277714

    Hello Everyone

    I hope that everyone is having a great weekend.

    I am looking over some tables and index plan that is currently in place. I see some queries that use other columns that have a non-clustered index, but then also adds one column that is not in the index. The one column currently has all NULL values. I am trying to learn how an index works with NULLs. I would greatly appreciate any advice on using / creating index on a column with NULL values. I have read the BOL, but still a little uncertain about this topic.

    How would this affect the performance of an index?

    I greatly appreciate any and all comments/suggestions.

    Thanks in advance

    Andrew SQLDBA

  • May 11, 2013 at 7:37 am

    #1614382

    No effect. As far as an index is concerned, null is just another value.

    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

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass

  • May 11, 2013 at 10:22 am

    #1614388

    Thanks Gila

    Greatly appreciate your time. You always have the answer to my odd type questions.

    Andrew SQLDBA

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