PostgreSQL's array_agg
function can be used to aggregate a column into an
array. Consider the following column:
> select num from generate_series(1,5) as num;
num
-----
1
2
3
4
5
By wrapping the array_agg
aggregate function around num
we are able to
aggregate the values in that column into an array, like so:
> select array_agg(num) from generate_series(1,5) as num;
array_agg
-------------
{1,2,3,4,5}
See the docs on aggregate functions for more details.