Re: Fast function, slow SQL
sql 2 has to examine a billion rows (876*1176*1176).
sql 1 & 3 elicit the optimiser's dependent subquery mechanisms, which are smarter in 5.6 but as you illustrate, not smart enough yet. I bet sql 1 & 3 would've been a lot slower in 5.0.
The function version of the query avoids all those pits of despair---it just has to peek into a `tableb` index to get its values.
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May 10, 2013 02:13AM
Re: Fast function, slow SQL
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June 01, 2013 12:46AM
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