>>>>> "Andrew" == Andrew Gierth <andrew(at)tao11(dot)riddles(dot)org(dot)uk> writes:
Andrew> Unfortunately, the planner isn't smart enough yet to know that
Andrew> these two are equivalent,
oops, I edited the second one before posting in a way that made them not
be equivalent: adding a "group by x0.item_id" in both subqueries in
method 2 makes them equivalent again. Without that, the result differs
slightly if there are no matching color or image rows (NULL vs. empty
array).
--
Andrew (irc:RhodiumToad)