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Question on Index usage

  • February 10, 2006 at 11:22 am

    #90681

    Hi All,

     I have an index consisting of three columns of a table say col A,B and C.

    If my query uses only col A , or only col A and B in the where clause , will the above index be utilized by the query?

     

     

    Thanks,

    Rajesh

  • February 10, 2006 at 11:34 am

    #620247

    Yes

    Provided your query uses Col A the index will be used.

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  • February 10, 2006 at 11:41 am

    #620250

    Thanks for the responding to my post.

     

     

     

  • February 10, 2006 at 11:53 am

    #620252

    The answer is "maybe".

    It depends on type of index and data distribution. If you query on A, and there are large numbers of repeating values of A in the index, and the index is non-clustered, the optimizer may decide it is not selective enough and not use the index.

     

  • February 10, 2006 at 2:11 pm

    #620283

    The answer is "maybe".

    It depends on type of index and data distribution. If you query on A, and there are large numbers of repeating values of A in the index, and the index is non-clustered, the optimizer may decide it is not selective enough and not use the index.

     

     

    Good to know this fact. I'll definitely keep this in mind.

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