Home Forums SQL Server 2008 SQL Server 2008 - General “SELECT 1″ rather than a “SELECT *” when using an EXISTS or a NOT EXISTS clause”. RE: “SELECT 1? rather than a “SELECT *” when using an EXISTS or a NOT EXISTS clause”.

  • February 12, 2011 at 1:20 am

    #1285997

    amenjonathan (2/11/2011)

    I also use SELECT NULL.

    Personally if something is faster and there's virtually no complexity difference, I use the faster version. Why waste where there is no need is my motto.

    The point is, it's not significantly faster, it's a couple of nanoseconds at best. It's micro-optimisation, it's a waste of time for no value.

    Use EXISTS (Select *, EXISTS (Select 1, EXISTS (Select NULL, or any other form as they are not going to make anything resembling a noticeable difference.

    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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