Your First PL/pgSQL Function - PostgreSQL Server Programming - page 71

FOR row IN EXECUTE
'SELECT * FROM job_queue q WHERE NOT
processed LIMIT 100'
LOOP
CASE q.process_type
WHEN 'archive_point_of_sale'
THEN INSERT INTO hist_orders (...)
SELECT ... FROM orders
INNER JOIN order_detail ...
INNER JOIN item ...;
WHEN 'prune_archived_orders'
THEN DELETE FROM order_detail
WHERE order_id in (SELECT
order_id FROM hist_orders);
DELETE FROM orders
WHERE order_id IN (SELECT
order_id FROM hist_orders);
ELSE
RAISE NOTICE 'Unknown process_type: %',
q.process_type;
END;