Fixed #27587 -- Adding examples of QuerySet.query.__str__() to docs.

docs/intro/tutorial02.txt

@@ -473,8 +473,14 @@ Save these changes and start a new Python interactive shell by running
     >>> from polls.models import Choice, Question
 
     # Make sure our __str__() addition worked.
-    >>> Question.objects.all()
+    >>> q = Question.objects.all()
+    >>> q
     <QuerySet [<Question: What's up?>]>
+    # Print the SQL used to query the database
+    >>> from pprint import pprint
+    >>> pprint(str(q.query))
+    ('SELECT "polls_question"."id", "polls_question"."question_text", '
+    '"polls_question"."pub_date" FROM "polls_question"')
 
     # Django provides a rich database lookup API that's entirely driven by
     # keyword arguments.

docs/topics/db/queries.txt

@@ -336,6 +336,19 @@ objects from the database. However, that's far from all there is; see the
 :ref:`QuerySet API Reference <queryset-api>` for a complete list of all the
 various :class:`~django.db.models.query.QuerySet` methods.
 
+
+Printing the ``QuerySet`` SQL
+--------------------------
+
+When debugging a query, it may be useful to see the SQL generated by a
+queryset. You may do this by converting the ``query`` attribute to a string.
+
+    >>> q = Entry.objects.all()
+    >>> str(q.query)
+
+This prints the SQL that is used to query the database. From there, you may
+looks for unexpected clauses, etc.
+
 .. _limiting-querysets:
 
 Limiting ``QuerySet``\s