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Thread: PLEASE HELP!!!!

  1. #1
    RJ Guest

    Default PLEASE HELP!!!!

    does the order of where clauses linking tables together in an SQL statement have any impact on the speed of the statement if some tables are much larger than others?(i.e. if you have 'where x.a=y.a and x.b=z.b and x.c=w.c', and y is a much larger table than either z or w, would it make more sense to have the z and w table where clauses come before the y one).

  2. #2
    Join Date
    Dec 1969

    Default Most definitely...

    ...You&#039;ll always want to try and limit the maximum number of records possible towards the beginning of your WHERE clause. Plus, be aware of how your indexes are structured and make sure your WHERE clause column order matches the structure of the index.<BR><BR>Example: If you have colA and colB together in one index, make sure your reference colA in the WHERE clause before your reference colB

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