merge r6591, r6592 from 0.5 branch for PGInterval etc. /extract

2 files changed, 7 insertions, 0 deletions

diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py
index a71984be4..1d7240fbf 100644
--- a/lib/sqlalchemy/dialects/postgresql/base.py
+++ b/lib/sqlalchemy/dialects/postgresql/base.py
@@ -110,6 +110,10 @@ class INTERVAL(sqltypes.TypeEngine):
     
     def adapt(self, impltype):
         return impltype(self.precision)
+
+    @property
+    def _type_affinity(self):
+        return sqltypes.Interval
         
 PGInterval = INTERVAL
 
diff --git a/lib/sqlalchemy/sql/util.py b/lib/sqlalchemy/sql/util.py
index 7bcc8e7d7..1b4bc67fc 100644
--- a/lib/sqlalchemy/sql/util.py
+++ b/lib/sqlalchemy/sql/util.py
@@ -104,6 +104,9 @@ def determine_date_affinity(expr):
         left_affin, right_affin = \
             determine_date_affinity(expr.left), \
             determine_date_affinity(expr.right)
+
+        if left_affin is None or right_affin is None:
+            return None
         
         if operators.is_commutative(expr.operator):
             key = tuple(sorted([left_affin, right_affin], key=lambda cls:cls.__name__))