diff --git a/db/routines/vn/procedures/sales_merge.sql b/db/routines/vn/procedures/sales_merge.sql
index a91268c2fc..3dd01f9bcf 100644
--- a/db/routines/vn/procedures/sales_merge.sql
+++ b/db/routines/vn/procedures/sales_merge.sql
@@ -1,5 +1,5 @@
-DELIMITER $$
-CREATE OR REPLACE DEFINER=`root`@`localhost` PROCEDURE `vn`.`sales_merge`(vTicketFk INT)
+DELIMITER $$
+CREATE OR REPLACE DEFINER=`root`@`localhost` PROCEDURE `vn`.`sales_merge`(vTicketFk INT)
 BEGIN
 	DECLARE EXIT HANDLER FOR SQLEXCEPTION
 	BEGIN
@@ -8,19 +8,21 @@ BEGIN
 	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;          
+			GROUP BY s.itemFk, s.price, s.discount;
 
 	START TRANSACTION;
 
 	UPDATE sale s 
 			JOIN tSalesToPreserve stp ON stp.id = s.id
-		SET quantity = newQuantity
+		SET s.quantity = newQuantity
 		WHERE s.ticketFk = vTicketFk;
 
 	DELETE s.*
@@ -35,5 +37,5 @@ BEGIN
 	COMMIT;
 
 	DROP TEMPORARY TABLE tSalesToPreserve;
-END$$
-DELIMITER ;
+END$$
+DELIMITER ;