salix/db/routines/vn/procedures/sales_merge.sql

DELIMITER $$
CREATE OR REPLACE DEFINER=`root`@`localhost` PROCEDURE `vn`.`sales_merge`(vTicketFk INT)
BEGIN
	DECLARE EXIT HANDLER FOR SQLEXCEPTION
	BEGIN
		ROLLBACK;
		RESIGNAL;
	END;

	CREATE OR REPLACE TEMPORARY TABLE tSalesToPreserve
		(PRIMARY KEY (id))
		ENGINE = MEMORY
		SELECT s.id, s.itemFk, SUM(s.quantity) newQuantity
			FROM sale s
				JOIN item i ON i.id = s.itemFk
				JOIN itemType it ON it.id = i.typeFk
			WHERE s.ticketFk = vTicketFk
				AND it.isMergeable
			GROUP BY s.itemFk, s.price, s.discount;

	START TRANSACTION;

	UPDATE sale s 
			JOIN tSalesToPreserve stp ON stp.id = s.id
		SET s.quantity = newQuantity
		WHERE s.ticketFk = vTicketFk;

	DELETE s.*
		FROM sale s
			LEFT JOIN tSalesToPreserve stp ON stp.id = s.id
			JOIN item i ON i.id = s.itemFk
			JOIN itemType it ON it.id = i.typeFk
		WHERE s.ticketFk = vTicketFk
			AND stp.id IS NULL
			AND it.isMergeable;

	COMMIT;

	DROP TEMPORARY TABLE tSalesToPreserve;
END$$
DELIMITER ;