Re: RFC: array_agg() per SQL:200n
Joe Conway <mail@joeconway.com>
From: Joe Conway <mail@joeconway.com>
To: Jeff Davis <pgsql@j-davis.com>
Cc: Neil Conway <neilc@samurai.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2008-01-29T01:59:45Z
Lists: pgsql-hackers
Jeff Davis wrote: > On Sun, 2008-01-27 at 22:11 -0800, Neil Conway wrote: >> p. 564 discusses the required behavior. The result of array_agg() is an >> array with one element per input value, sorted according to the optional >> ORDER BY clause. NULL input values are included in the array, and the >> result for an empty group is NULL, not an empty array. Note that per >> page 66, I'd expect array values in the input to array_agg() not to be >> flattened. > > Should there be an inverse operator (a SRF, in this case) that returns a > set from an array? Yes -- see UNNEST Joe