- added standalone distinct() function in addition to column.distinct()

[ticket:558]

1 files changed, 9 insertions, 1 deletions

diff --git a/lib/sqlalchemy/sql.py b/lib/sqlalchemy/sql.py
index f9ac753fa..92b51dd25 100644
--- a/lib/sqlalchemy/sql.py
+++ b/lib/sqlalchemy/sql.py
@@ -34,7 +34,7 @@ __all__ = ['AbstractDialect', 'Alias', 'ClauseElement', 'ClauseParameters',
            'Compiled', 'CompoundSelect', 'Executor', 'FromClause', 'Join',
            'Select', 'Selectable', 'TableClause', 'alias', 'and_', 'asc',
            'between_', 'bindparam', 'case', 'cast', 'column', 'delete',
-           'desc', 'except_', 'except_all', 'exists', 'extract', 'func', 'modifier',
+           'desc', 'distinct', 'except_', 'except_all', 'exists', 'extract', 'func', 'modifier',
            'insert', 'intersect', 'intersect_all', 'join', 'literal',
            'literal_column', 'not_', 'null', 'or_', 'outerjoin', 'select',
            'subquery', 'table', 'text', 'union', 'union_all', 'update',]
@@ -375,6 +375,11 @@ def not_(clause):
 
     return clause._negate()
 
+def distinct(expr):
+    """return a ``DISTINCT`` clause."""
+    
+    return _UnaryExpression(expr, operator="DISTINCT")
+
 def between(ctest, cleft, cright):
     """Return a ``BETWEEN`` predicate clause.
 
@@ -749,8 +754,11 @@ class _FunctionGenerator(object):
         return _Function(self.__names[-1], packagenames=self.__names[0:-1], *c, **o)
 
 func = _FunctionGenerator()
+
+# TODO: use UnaryExpression for this instead ?
 modifier = _FunctionGenerator(group=False)
 
+    
 def _compound_select(keyword, *selects, **kwargs):
     return CompoundSelect(keyword, *selects, **kwargs)