sql_select_insert

BEGIN
    LOOP
        -- first check if this number is already present in list with id 1
		SELECT * from test_co.list_numbers where lists_id='1' and numbers_id= '2';
        IF found THEN
            RETURN;
        END IF;
        -- not there, so try to insert the phone_id and the list_id
        -- if someone else inserts the same key concurrently,
        -- we could get a unique-key failure
        BEGIN
            --if it's not present, then insert it
 	    INSERT INTO test_co.list_numbers (lists_id, numbers_id) VALUES (1, 2);
            RETURN;
        EXCEPTION WHEN unique_violation THEN
            -- do nothing, and loop to try the UPDATE again
        END;
    END LOOP;
END;