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Message Posted: Thu, 04 Jan 2001 @ 22:58:44 GMT

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Subj:   Re: Union Conundrum
From:   Sam Sterling

I hate to ask the obvious, but... Are statistics current?

You might want to include the query to look at the joins, in light of the statistics. It is possible that the sum of the answer sets of the UNIONed answer sets is larger than you might think (it is possible (I'm not exactly sure how, though) that depending on the join criteria you may get more rows in the UNIONed because more rows would qualify for each SELECT individually and be double counted in the final answer set).

I'm definitely not the guru on arcane things that the optimizer might do. I'd have to beat this one into submission just like you.

Sam Sterling

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