DROP TRIGGER trg_upd_qty;
DELIMITER //
CREATE TRIGGER trg_upd_qty AFTER INSERT ON tblinvoiceproduct

	FOR EACH ROW

	DECLARE in_stock_qty INTEGER;
	DECLARE ordered_qty INTEGER = NEW.invproQuantity;

	BEGIN
		SELECT proInStock INTO in_stock_qty FROM tblproduct WHERE proID = NEW.invproProductID;

		UPDATE tblproduct SET proInStock = (in_stock_qty - ordered_qty) WHERE proID = :NEW.invproProductID;
	END;
DELIMITER ;