diff --git a/database/3.0.2_to_3.1.0.sql b/database/3.0.2_to_3.1.0.sql
index 84c87e69c..0fc27059e 100644
--- a/database/3.0.2_to_3.1.0.sql
+++ b/database/3.0.2_to_3.1.0.sql
@@ -358,7 +358,7 @@ ALTER TABLE ospos_items MODIFY unit_price decimal(15,2) NOT NULL;
 ALTER TABLE ospos_receivings MODIFY comment text NOT NULL;
 ALTER TABLE ospos_receivings_items MODIFY discount_percent decimal(15,2) NOT NULL DEFAULT '0.00';
 ALTER TABLE ospos_receivings_items MODIFY item_unit_price decimal(15,2) NOT NULL;
-ALTER TABLE ospos_sales MODIFY comment text NOT NULL;
+ALTER TABLE ospos_sales MODIFY comment text DEFAULT NULL;
 ALTER TABLE ospos_sales_items MODIFY discount_percent decimal(15,2) NOT NULL DEFAULT '0.00';
 ALTER TABLE ospos_sales_items MODIFY item_unit_price decimal(15,2) NOT NULL;