diff --git a/Language/SQL/SimpleSQL/Parse.lhs b/Language/SQL/SimpleSQL/Parse.lhs
index ba5f684..82cd780 100644
--- a/Language/SQL/SimpleSQL/Parse.lhs
+++ b/Language/SQL/SimpleSQL/Parse.lhs
@@ -1564,8 +1564,9 @@ TODO: change style
 > colConstraintDef =
 >     ColConstraintDef
 >     <$> (optionMaybe (keyword_ "constraint" *> names))
->     <*> (notNull <|> unique <|> primaryKey <|> check <|> references)
+>     <*> (nullable <|> notNull <|> unique <|> primaryKey <|> check <|> references)
 >   where
+>     nullable = ColNullableConstraint <$ keyword "null"
 >     notNull = ColNotNullConstraint <$ keywords_ ["not", "null"]
 >     unique = ColUniqueConstraint <$ keyword_ "unique"
 >     primaryKey = ColPrimaryKeyConstraint <$ keywords_ ["primary", "key"]
diff --git a/Language/SQL/SimpleSQL/Syntax.lhs b/Language/SQL/SimpleSQL/Syntax.lhs
index 22d61c8..3dfd440 100644
--- a/Language/SQL/SimpleSQL/Syntax.lhs
+++ b/Language/SQL/SimpleSQL/Syntax.lhs
@@ -571,7 +571,8 @@ I'm not sure if this is valid syntax or not.
 >     deriving (Eq,Show,Read,Data,Typeable)
 
 > data ColConstraint =
->     ColNotNullConstraint
+>     ColNullableConstraint
+>   | ColNotNullConstraint
 >   | ColUniqueConstraint
 >   | ColPrimaryKeyConstraint
 >   | ColReferencesConstraint [Name] (Maybe Name)