"Oliveiros d'Azevedo Cristina" <[email protected]> wrote: > What is faster? A JOIN or a WHERE a IN (SELECT ... ) On 8.4 and later an EXISTS or NOT EXISTS will use semi-join or anti-join (respectively). These should usually be much faster than the IN (SELECT DISTINCT ... ) technique. Be careful of the difference in semantics between NOT EXISTS and NOT IN if any of the columns involved in the matching can be null -- they are *not* the same thing. -Kevin
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