2016-11-19 3:59 GMT+01:00 Douglas Doole <dougdo...@gmail.com>: > > On Fri, Nov 18, 2016 at 12:47 AM Pavel Stehule <pavel.steh...@gmail.com> > wrote: > > Isn't possible in this case push equivalence before aggregation? > > > If I'm understanding you correctly, that would lead to wrong results. > Here's a simple example: > > CREATE VIEW v AS SELECT MIN(a) m FROM t; > > and table T contains: > > T:A > --- > 1 > 2 > 3 > > SELECT * FROM v WHERE m = 2 > > The minimum value of A is 1, so the query should return no rows. > > However, if we filter first we'd be effectively doing the query: > > SELECT MIN(a) m FROM > (SELECT a FROM t WHERE a=2) AS v(a) > > The subquery is going to return an intermediate result of: > > V:A > --- > 2 > > And the minimum of that is 2, which is the wrong answer. >
yes, you have true, thank you for correcting Regards Pavel > > - Doug > Salesforce >
