PostgresQL SQL: Converting results to array
You want to use array_agg, this should work:
SELECT i_adgroup_id, array_agg(i_category_id)FROM adgroupcategories_brWHERE i_adgroup_id IN( SELECT i_adgroup_id FROM adgroupusers_br WHERE i_user_id = 103713)GROUP BY i_adgroup_id;Note that i_category_id is no longer in the GROUP BY as it is now being aggregated.