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do you have evidence that subselects are inefficient? (i don't know the answer myself - i would hope that a database can do pretty decent optimisation, but per
by andrewcooke 15y ago
do you have evidence that subselects are inefficient? (i don't know the answer myself - i would hope that a database can do pretty decent optimisation, but perhaps this is the db equivalent of "given a sufficiently good compiler...").
- ibdknox 15y agoIt depends very heavily on which RDBMS you use as to what ends up optimized. It's a relatively well trafficked subject, a simple google search turns up quite a few results, for example: http://www.mysqldbahelp.com/2010/03/subselect-vs-join-performanace.html http://www.mysqldbahelp.com/2010/03/subselect-vs-join-perfor... Disclaimer: I didn't validate his results ;)