Re: multiple column to onec column

CREATE AGGREGATE array_accum (anyelement)
(   sfunc = array_append,   stype = anyarray,   initcond = '{}'
);

 

SELECT r.role_name, array_accum(permission) from roles r, roles_permissions rp group by r.role_name;

and the result:

role_name |              array_accum              

-----------+---------------------------------------

 role2     | {permission1,permission2,permission1}

 role1     | {permission1,permission2,permission1}