Tom Lane wrote:
Joe Conway <[EMAIL PROTECTED]> writes:
Sorry for the slow response -- I'm at the airport just heading home from
a marathon 30 day business trip.
Yow. Hope you get some time off...
Yeah, I just took a week. Next week I'm back to work and the week after
that I'm back to Germany for a few...
On looking at the code, I notice that this somewhat-related case works:
regression=# select array[null::text[], null::text[]];
array
-------
{}
(1 row)
The reason is that null inputs are just ignored in ExecEvalArray. So
one pretty simple patch would be to ignore zero-dimensional inputs too.
This would have implications for mixed inputs though: instead of
regression=# select array['{}'::text[], '{a,b,c}'::text[]];
ERROR: multidimensional arrays must have array expressions with matching
dimensions
you'd get behavior like
regression=# select array[null::text[], '{a,b,c}'::text[]];
array
-----------
{{a,b,c}}
(1 row)
Which of these seems more sane?
I'm not sure I love either. I would think both NULL and empty array
expressions should be disallowed in this scenario, i.e.:
regression=# select array['{}'::text[], '{a,b,c}'::text[]];
ERROR: multidimensional arrays must have array expressions with
matching dimensions
regression=# select array[NULL::text[], '{a,b,c}'::text[]];
ERROR: multidimensional arrays must have array expressions with
matching dimensions
In both cases you are trying to construct a multidimensional array with
inconsistent dimensions.
On the other hand, building an N-dimension array from entirely empty
array expressions should just produce an empty array, while using all
NULL expressions should produce an N-dim array full of NULLs.
But as I've opined before, all of this seems to me to be much cleaner if
arrays were always one-dimensional, and array elements could also be
nested arrays (per SQL 2003). If we said that the cardinality of the
nested array is an integral part of the datatype, then I think you would
have:
regression=# select array['{}'::text[], '{a,b,c}'::text[]];
ERROR: nested arrays must have array expressions with matching
dimensions
regression=# select array[NULL::text[], '{a,b,c}'::text[]];
array
-----------
{NULL, {a,b,c}}
(1 row)
So maybe this is the behavior we should shoot for now?
Joe
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