Re: multiple column to onec column

thanks , this is a example of my application.

the ans is here, http://www.postgresql.org/docs/9.0/static/xaggr.html

sql command:

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}