Forum Post: RE: Got asked a Newbie Question: Nested -vs- Join

  • Thread starter Thread starter Tim Kuehn
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Tim Kuehn

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The AVM doesn't do server-side joins - the upper level of the WHERE phrase is resolved by a db engine, and then each record of the subordinate portions of the WHERE clause are evaluated for a match with the higher level phrase a record at a time. This all happens "under the covers" when the FOR EACH / WHERE is all in one statement. There's some additional overhead when the WHERE conditions are split into two FOR EACH / WHERE statements, and that's where the performance hit comes in.

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