Joe Conway <[EMAIL PROTECTED]> writes:Same here; this would be:
array_upper(a || b) == array_upper(a) + CARDINALITY(b)
and would work just fine. Note that if array-a is NULL, then the spec defines a || b as NULL. See section 6.35:
Why are you talking about when a is NULL? The original question was for when a was an empty array. That's not an unknown value, it's known to be an array containing no elements.
Did you even look at my examples at the end of the post? I showed your example, with an empty array, handled correctly. The mention of a NULL array was only for completeness.
It sounds like this is the same type of confusion that led to Oracle treating empty strings as NULL, which causes no end of headaches.
ISTM that you're the one who's confused. There is a very clear distinction between a NULL array and an empty array in the present implementation. They are *not* treated the same:
regression=# select '{}'::int[], NULL::int[];
int4 | int4
------+------
{} |
(1 row)regression=# select '{}'::int[] is NULL, NULL::int[] is NULL;
?column? | ?column?
----------+----------
f | t
(1 row)You seem to be saying that because the output of certain functions that operate on empty arrays is NULL, it somehow implies that the array is being treated as NULL -- that's just plain incorrect.
My argument was that having to write a special case here makes it pretty clear
the idea of equating {} with NULL is the wrong interface.
But they're not being equated (see above), so I don't see where there's an issue.
Joe
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