-- -- ec_shipment_cost/1 -- create or replace function ec_shipment_cost( integer ) returns numeric as $$ DECLARE v_shipment_id alias for $1; v_price numeric; v_shipping numeric; v_certificate numeric; v_tax numeric; BEGIN v_price := ec_shipment_price(v_shipment_id); v_shipping := ec_shipment_shipping(v_shipment_id); v_tax := ec_shipment_tax(v_shipment_id); v_certificate := ec_shipment_gift_certificate(v_shipment_id); return v_price + v_shipping - v_certificate + v_tax; END;$$ language plpgsql;