Merge pull request 'feat: refs #7325 item_getBalance' (!2397) from 7325-item_getBalance into dev

Reviewed-on: #2397
Reviewed-by: Sergio De la torre <sergiodt@verdnatura.es>

db/routines/vn/procedures/item_getBalance.sql

@@ -179,7 +179,7 @@ BEGIN
 				LEFT JOIN alertLevel a ON a.id = t.alertLevel;
 
 	ELSE
-		SELECT SUM(`in`) - SUM(`out`) INTO @a
+		SELECT IFNULL(SUM(IFNULL(`in`, 0)) - SUM(IFNULL(`out`, 0)), 0) INTO @a
 			FROM tItemDiary
 			WHERE shipped < vDate;