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Having Clause or Sub-Select ?

  • October 1, 2002 at 1:56 pm

    #79473

    In a select statment, which causes more overhead, using a sub-select in the where clause or using Having?

  • October 2, 2002 at 3:45 am

    #437609

    Could you give more details about your need and with an example if it's possible.

    Thanks

    JMackels Developper/DBA

  • October 2, 2002 at 4:09 am

    #437615

    As with any query it can vary. In some situations it may be subselect has more overhead than having, but other might be the opposite. The best way is to try both solutions and compare the time to output, the cpu utilization and read duration amounts and the overall query execution plan.

    "Don't roll your eyes at me. I will tape them in place." (Teacher on Boston Public)

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