Markus Bertheau ☭ wrote:
Hmm, this gets really complicated and inconsistent. Complicated means
unusable. What about modifying the dimension syntax such that the second
number means number of elements instead of upper bound? That particular
problem would go away then, and array_upper('[0:0]={}'::int[]) can
return the correct 0 then.
What I'm actually worrying about is that array_upper(array(select 1
where false)) returns 0.
An option would be to drop the possibility to let the array start at
another index than 0. I don't know why it was decided to do that in the
first place. It seems a rather odd feature to me.
Actually I like both of these ideas, and have advocated the second one
myself before. But it isn't backward compatible -- anyone else have an
opinion? SQL2003 actually specifies that an array *should* start at 1:
4.10.2 Arrays
An array is a collection A in which each element is associated with
exactly one ordinal position in A. If n is the cardinality of A, then
the ordinal position p of an element is an integer in the range 1 (one)
≤ p ≤ n.
Joe
---------------------------(end of broadcast)---------------------------
TIP 9: the planner will ignore your desire to choose an index scan if your
joining column's datatypes do not match
