[hotfix] fixed the mysql syntax error issue on stock ledger report (#10442)

diff --git a/erpnext/stock/report/stock_ledger/stock_ledger.py b/erpnext/stock/report/stock_ledger/stock_ledger.py
index ec55cec..4a8868a 100644
--- a/erpnext/stock/report/stock_ledger/stock_ledger.py
+++ b/erpnext/stock/report/stock_ledger/stock_ledger.py
@@ -73,7 +73,9 @@
 		conditions.append("""item_code in (select name from tabItem
 			{item_conditions})""".format(item_conditions=item_conditions))
 	if filters.get("warehouse"):
-		conditions.append(get_warehouse_condition(filters.get("warehouse")))
+		warehouse_condition = get_warehouse_condition(filters.get("warehouse"))
+		if warehouse_condition:
+			conditions.append(warehouse_condition)
 	if filters.get("voucher_no"):
 		conditions.append("voucher_no=%(voucher_no)s")
 	if filters.get("batch_no"):