- [bug] Fixed bug in over() construct whereby

    passing an empty list for either partition_by
    or order_by, as opposed to None, would fail
    to generate correctly.
    Courtesy Gunnlaugur Por Briem.
    [ticket:2574]

1 files changed, 11 insertions, 11 deletions

diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index 3b17c040c..d97c048a9 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -530,17 +530,17 @@ class SQLCompiler(engine.Compiled):
                     cast.typeclause._compiler_dispatch(self, **kwargs))
 
     def visit_over(self, over, **kwargs):
-        x = "%s OVER (" % over.func._compiler_dispatch(self, **kwargs)
-        if over.partition_by is not None:
-            x += "PARTITION BY %s" % \
-                over.partition_by._compiler_dispatch(self, **kwargs)
-            if over.order_by is not None:
-                x += " "
-        if over.order_by is not None:
-            x += "ORDER BY %s" % \
-                over.order_by._compiler_dispatch(self, **kwargs)
-        x += ")"
-        return x
+         return "%s OVER (%s)" % (
+             over.func._compiler_dispatch(self, **kwargs),
+             ' '.join(
+                 '%s BY %s' % (word, clause._compiler_dispatch(self, **kwargs))
+                 for word, clause in (
+                     ('PARTITION', over.partition_by),
+                     ('ORDER', over.order_by)
+                 )
+                 if clause is not None and len(clause)
+             )
+         )
 
     def visit_extract(self, extract, **kwargs):
         field = self.extract_map.get(extract.field, extract.field)