1 files changed, 40 insertions, 2 deletions

diff --git a/lib/sqlalchemy/orm/query.py b/lib/sqlalchemy/orm/query.py
index 60948293b..7b2ea7977 100644
--- a/lib/sqlalchemy/orm/query.py
+++ b/lib/sqlalchemy/orm/query.py
@@ -1145,7 +1145,8 @@ class Query(object):
 
     @_generative()
     def with_hint(self, selectable, text, dialect_name='*'):
-        """Add an indexing hint for the given entity or selectable to
+        """Add an indexing or other executional context
+        hint for the given entity or selectable to
         this :class:`.Query`.
 
         Functionality is passed straight through to
@@ -1153,11 +1154,35 @@ class Query(object):
         with the addition that ``selectable`` can be a
         :class:`.Table`, :class:`.Alias`, or ORM entity / mapped class
         /etc.
+
+        .. seealso::
+
+            :meth:`.Query.with_statement_hint`
+
         """
-        selectable = inspect(selectable).selectable
+        if selectable is not None:
+            selectable = inspect(selectable).selectable
 
         self._with_hints += ((selectable, text, dialect_name),)
 
+    def with_statement_hint(self, text, dialect_name='*'):
+        """add a statement hint to this :class:`.Select`.
+
+        This method is similar to :meth:`.Select.with_hint` except that
+        it does not require an individual table, and instead applies to the
+        statement as a whole.
+
+        This feature calls down into :meth:`.Select.with_statement_hint`.
+
+        .. versionadded:: 1.0.0
+
+        .. seealso::
+
+            :meth:`.Query.with_hint`
+
+        """
+        return self.with_hint(None, text, dialect_name)
+
     @_generative()
     def execution_options(self, **kwargs):
         """ Set non-SQL options which take effect during execution.
@@ -2591,6 +2616,19 @@ class Query(object):
                 SELECT 1 FROM users WHERE users.name = :name_1
             ) AS anon_1
 
+        The EXISTS construct is usually used in the WHERE clause::
+
+            session.query(User.id).filter(q.exists()).scalar()
+
+        Note that some databases such as SQL Server don't allow an
+        EXISTS expression to be present in the columns clause of a
+        SELECT.    To select a simple boolean value based on the exists
+        as a WHERE, use :func:`.literal`::
+
+            from sqlalchemy import literal
+
+            session.query(literal(True)).filter(q.exists()).scalar()
+
         .. versionadded:: 0.8.1
 
         """