• SQLKnowItAll (12/26/2012)


    If it is as simple as what you provided... creating an index on Table2.FieldB will "probably" help.

    Depends how selective the filter is. It's definitely not a covering index, so depends on whether the cost of the key lookups is judged low enough (and that's assuming the filter's SARGable in the first place)

    My gut feel is that it probably won't help. There's an index that appears covering, though the columns are in the wrong order to support the filter)

    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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