Fixed #7327 -- Added documentation and test case for defining subqueries. Thanks, Sebastian Noack.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@7625 bcc190cf-cafb-0310-a4f2-bffc1f526a37

docs/db-api.txt

@@ -1373,6 +1373,17 @@ SQL equivalent::
 
     SELECT ... WHERE id IN (1, 3, 4);
 
+You can also use a queryset to dynamically evaluate the list of values
+instead of providing a list of literal values. The queryset must be
+reduced to a list of individual values using the ``values()`` method, 
+and then converted into a query using the ``query`` attribute::
+
+    Entry.objects.filter(blog__in=Blog.objects.filter(name__contains='Cheddar').values('pk').query)
+
+This queryset will be evaluated as subselect statement::
+
+    SELET ... WHERE blog.id IN (SELECT id FROM ... WHERE NAME LIKE '%Cheddar%')
+
 startswith
 ~~~~~~~~~~
 

tests/modeltests/many_to_one/models.py

@@ -175,6 +175,12 @@ False
 >>> Article.objects.filter(reporter__in=[r,r2]).distinct()
 [<Article: John's second story>, <Article: Paul's story>, <Article: This is a test>]
 
+# You can also use a queryset instead of a literal list of instances.
+# The queryset must be reduced to a list of values using values(), 
+# then converted into a query
+>>> Article.objects.filter(reporter__in=Reporter.objects.filter(first_name='John').values('pk').query).distinct()
+[<Article: John's second story>, <Article: This is a test>]
+
 # You need two underscores between "reporter" and "id" -- not one.
 >>> Article.objects.filter(reporter_id__exact=1)
 Traceback (most recent call last):