>The original statement was Re: Performance - union Thread #1534182 Message #1534224 : The EXISTS can be replaced with LEFT JOIN
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>(1) I do not see why you would need a LEFT JOIN - if you do you have to add : where .. is not null
>(2) You cannot just replace it. You need to add DISTINCT
>


The statement meant (not written) was that LEFT JOIN with IS NULL can be replaced with NOT EXISTS.

INNER JOIN and EXISTS are not equivalent if we're talking about 1:many or many to many type of relationship.