From a87ade7e30c80de93ec7ad8335d8714b494a58fb Mon Sep 17 00:00:00 2001
From: Benjamin Bach <benjaoming@gmail.com>
Date: Mon, 1 Dec 2014 00:02:43 +0100
Subject: [PATCH] [1.6.x] Documented a current limitation of multiple table
 annotation; refs #10060.

Backport of 4b23a6c7a9232cc07ec95fe98be17efbd4449822 from master
---
 docs/topics/db/aggregation.txt | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/docs/topics/db/aggregation.txt b/docs/topics/db/aggregation.txt
index 1024d6b0c2..90735c31a4 100644
--- a/docs/topics/db/aggregation.txt
+++ b/docs/topics/db/aggregation.txt
@@ -179,6 +179,17 @@ of the ``annotate()`` clause is a ``QuerySet``; this ``QuerySet`` can be
 modified using any other ``QuerySet`` operation, including ``filter()``,
 ``order_by()``, or even additional calls to ``annotate()``.
 
+.. admonition:: If in doubt, inspect the SQL query!
+
+    In order to understand what happens in your query, consider inspecting the
+    ``query`` property of your ``QuerySet``.
+
+    For instance, combining multiple aggregations with ``annotate()`` will
+    yield the wrong results, as `multiple tables are the cross joined`_,
+    resulting in duplicate row aggregations.
+
+.. _multiple tables are the cross joined: https://code.djangoproject.com/ticket/10060
+
 Joins and aggregates
 ====================