diff --git a/erpnext/stock/doctype/stock_ledger/stock_ledger.py b/erpnext/stock/doctype/stock_ledger/stock_ledger.py
index ff6de70..c1bfa96 100644
--- a/erpnext/stock/doctype/stock_ledger/stock_ledger.py
+++ b/erpnext/stock/doctype/stock_ledger/stock_ledger.py
@@ -139,7 +139,7 @@
 			elif purpose == 'Sales Return':
 				sql("update `tabSerial No` set status = 'Delivered', purchase_document_type = '', purchase_document_no = '' where name = '%s'" % serial_no)
 			else:
-				sql("update `tabSerial No` set docstatus = 2, status = 'Not in Use', purchase_document_type = '', purchase_document_no = '', purchase_date = '', purchase_rate = '', supplier = null, supplier_name = '', supplier_address = '', warehouse = '' where name = '%s'" % serial_no)
+				sql("update `tabSerial No` set docstatus = 2, status = 'Not in Use', purchase_document_type = '', purchase_document_no = '', purchase_date = null, purchase_rate = 0, supplier = null, supplier_name = '', supplier_address = '', warehouse = '' where name = '%s'" % serial_no)
 
 
 	# -------------------------------