loop through SELECT statement query results in a Trigger

[Ferindo Middleton]

Is there a way to loop through individual query records within a stored
procedure or trigger. If I have table called client_names (id SERIAL, first
name TEXT, middlename TEXT, lastname TEXT, suffix TEXT, pet_id INT,
properly_trained TEXT) and I have a trigger on it, I'd like to iterate
through individual query rows back at another table having a foreign key on
pet_id. For example:

CREATE TRIGGER update_clients_with_week_assignment_based_on_pet_id_in_pets_table
BEFORE INSERT
ON client_names
FOR EACH ROW
BEGIN
    (SELECT * FROM pets;)
 label1: LOOP

   IF (pets row.pet_type) = 4 THEN
   SET properly_trained = 1;
   ITERATE label1;
   END IF;
   LEAVE label1;
 END LOOP label1;
 SET @x = p1;
END

Is this possible. Can you loop through the query results of a SELECT
statement in a trigger, function, or procedure.

Ferindo