On Mar 25 10:11, george young wrote:
> On Mar 23 11:44, Don Maier <dMaier@genome.stanford.edu> wrote:
> > Conversely, is it possible to construct a (single column) result set
> > from a select expression on a one-dimensional array with an unknown
> > number of elements?
>
> Not so easy without a custom function.
But not that hard:
test=> SELECT id, val FROM t_arr;id | val
----+--------------- 1 | {1,2,3} 2 | {4,5,6} 3 | {7,8,9} 4 | {10,11,12,13}
(4 rows)
--
-- First Way
--
test=> SELECT id, val[s.i]
test-> FROM t_arr
test-> LEFT OUTER JOIN
test-> (SELECT g.s
test(> FROM generate_series(1, (SELECT max(array_upper(val, 1)) FROM t_arr)) AS g(s)
test(> ) AS s(i)
test-> ON (s.i <= array_upper(val, 1));id | val
----+----- 1 | 1 1 | 2 1 | 3 2 | 4 2 | 5 2 | 6 3 | 7 3 | 8 3 | 9 4 | 10 4 | 11 4 | 12 4 | 13
(13 rows)
--
-- Second Way (by using contrib/intagg)
--
SELECT id, int_array_enum(val) FROM t_arr;
Regards.
