4 files changed, 32 insertions, 6 deletions
diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index 46f111d2c..a734bb582 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -2610,7 +2610,9 @@ class SQLCompiler(Compiled):
 
         v = "VALUES %s" % ", ".join(
             self.process(
-                elements.Tuple(*elem).self_group(),
+                elements.Tuple(
+                    types=element._column_types, *elem
+                ).self_group(),
                 literal_binds=element.literal_binds,
             )
             for chunk in element._data
diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py
index ab8701dd6..75c1fc1bf 100644
--- a/lib/sqlalchemy/sql/elements.py
+++ b/lib/sqlalchemy/sql/elements.py
@@ -2497,11 +2497,28 @@ class Tuple(ClauseList, ColumnElement):
         """
         sqltypes = util.preloaded.sql_sqltypes
 
-        clauses = [
-            coercions.expect(roles.ExpressionElementRole, c) for c in clauses
-        ]
-        self.type = sqltypes.TupleType(*[arg.type for arg in clauses])
+        types = kw.pop("types", None)
+        if types is None:
+            clauses = [
+                coercions.expect(roles.ExpressionElementRole, c)
+                for c in clauses
+            ]
+        else:
+            if len(types) != len(clauses):
+                raise exc.ArgumentError(
+                    "Wrong number of elements for %d-tuple: %r "
+                    % (len(types), clauses)
+                )
+            clauses = [
+                coercions.expect(
+                    roles.ExpressionElementRole,
+                    c,
+                    type_=typ if not typ._isnull else None,
+                )
+                for typ, c in zip(types, clauses)
+            ]
 
+        self.type = sqltypes.TupleType(*[arg.type for arg in clauses])
         super(Tuple, self).__init__(*clauses, **kw)
 
     @property
diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py
index d60afdbac..b49fe92df 100644
--- a/lib/sqlalchemy/sql/selectable.py
+++ b/lib/sqlalchemy/sql/selectable.py
@@ -2397,6 +2397,10 @@ class Values(Generative, FromClause):
         self.literal_binds = kw.pop("literal_binds", False)
         self.named_with_column = self.name is not None
 
+    @property
+    def _column_types(self):
+        return [col.type for col in self._column_args]
+
     @_generative
     def alias(self, name, **kw):
         """Return a new :class:`_expression.Values`
diff --git a/lib/sqlalchemy/sql/sqltypes.py b/lib/sqlalchemy/sql/sqltypes.py
index 581573d17..09c7388ab 100644
--- a/lib/sqlalchemy/sql/sqltypes.py
+++ b/lib/sqlalchemy/sql/sqltypes.py
@@ -3074,7 +3074,9 @@ class NullType(TypeEngine):
 
     def literal_processor(self, dialect):
         def process(value):
-            return "NULL"
+            raise exc.CompileError(
+                "Don't know how to render literal SQL value: %r" % value
+            )
 
         return process
 
@@ -3131,6 +3133,7 @@ else:
     _type_map[unicode] = Unicode()  # noqa
     _type_map[str] = String()
 
+
 _type_map_get = _type_map.get