Re: [BUGS] BUG #14626: array_agg( anyarray ) unexpected error withmulti-valued single-dimension array

On Wed, Apr 19, 2017 at 1:03 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:

david.g.johnston@gmail.com writes:
> This doesn't, and should since the number of elements in the non-empty array
> shouldn't change the dimensionality logic.

> SELECT array_agg(CASE WHEN a = ARRAY[]::text[] THEN ARRAY['N/A']::text[]
> ELSE a END)
> FROM ( VALUES (1, ARRAY[]::text[]), (1, ARRAY['1','2']::text[]) ) vals (v,
> a)

Why do you think that should work?  You're asking array_agg to accumulate
a 1-D length-1 array and then a 1-D length-2 array.  There's no way to
make a rectangular 2-D array out of that, except perhaps by inventing
entries which isn't in array_agg's charter.

​

All this and all I really want is a friggin' "array_append / array_concat" aggregate function that accepts either scalars or matching "primary dimension" arrays - and treats empty arrays as no-ops.