Aggregate A Column Into An Array

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.