Re:For Want of a JOIN
by ivanhoe on Thursday December 22, 2022 @01:48PM
(#34096881)
Also databases (yup, MySQL I'm looking at you) got better at handling subqueries quickly, which makes the job of ORMs a lot easier.
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It's still (5.7) really bad sometimes. A simple `IN (subquery)` can sometimes run much better if the subquery is fetched and another round-trip query is made using literal values for the `IN (...)`. I'm sure there are plenty of other 'deoptimizing' query patterns that shouldn't be.