[thelist] SQL replace subquery with join
r937
rudy at r937.com
Tue Jan 5 13:16:38 CST 2010
> I'd probably still write the subquery version, as I think it looks more
elegant and it more obviously says what it does. At least to me :-)
i understand where you're coming from ;o)
now let's consider execution efficiency
any solution that returns all possible rows, only to throw many of them away
(e.g. david's MAX and HAVING trick) will be less efficient than a solution
that attempts to retrieve only one particular genre
and the NOT EXISTS solution is notoriously inefficient
only high-volume benchmarks can effectively resolve a scenario where a given
problem has multiple, often wildly different solutions
;o)
More information about the thelist
mailing list