- Unary expressions such as DISTINCT propagate their

type handling to result sets, allowing conversions like
unicode and such to take place.  [ticket:1420]

2 files changed, 5 insertions, 6 deletions

diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index 5140b7f20..6af65ec14 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -405,8 +405,8 @@ class DefaultCompiler(engine.Compiled):
         else:
             return text
 
-    def visit_unary(self, unary, **kwargs):
-        s = self.process(unary.element)
+    def visit_unary(self, unary, **kw):
+        s = self.process(unary.element, **kw)
         if unary.operator:
             s = self.operator_string(unary.operator) + " " + s
         if unary.modifier:
diff --git a/lib/sqlalchemy/sql/expression.py b/lib/sqlalchemy/sql/expression.py
index b5eb0eee9..0dae6716d 100644
--- a/lib/sqlalchemy/sql/expression.py
+++ b/lib/sqlalchemy/sql/expression.py
@@ -400,8 +400,8 @@ def not_(clause):
 
 def distinct(expr):
     """Return a ``DISTINCT`` clause."""
-
-    return _UnaryExpression(expr, operator=operators.distinct_op)
+    expr = _literal_as_binds(expr)
+    return _UnaryExpression(expr, operator=operators.distinct_op, type_=expr.type)
 
 def between(ctest, cleft, cright):
     """Return a ``BETWEEN`` predicate clause.
@@ -1476,8 +1476,7 @@ class _CompareMixin(ColumnOperators):
 
     def distinct(self):
         """Produce a DISTINCT clause, i.e. ``DISTINCT <columnname>``"""
-
-        return _UnaryExpression(self, operator=operators.distinct_op)
+        return _UnaryExpression(self, operator=operators.distinct_op, type_=self.type)
 
     def between(self, cleft, cright):
         """Produce a BETWEEN clause, i.e. ``<column> BETWEEN <cleft> AND <cright>``"""