On 11/21/12 3:16 PM, Andrew Dunstan wrote:
> One open question regarding this feature is whether this should return
> NULL or '[]' for 0 rows. Currently it returns NULL but I could be
> convinced to return '[]', and the change would be very small.
Although my intuition would be [], the existing concatenation-like
aggregates return null for no input rows, so this probably ought to be
consistent with those.