>>>>> "Andrew" == Andrew Gierth <and...@tao11.riddles.org.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)

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