From 08855064cd1b98cf0c00f902de89a94d0564c459 Mon Sep 17 00:00:00 2001
From: Mauro George <maurogot@gmail.com>
Date: Sun, 1 Jun 2014 10:58:24 -0300
Subject: Add Total of grouped items to AR query interface on guides

[ci skip]
---
 guides/source/active_record_querying.md | 34 +++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/guides/source/active_record_querying.md b/guides/source/active_record_querying.md
index ee8cf4ade6..b2d71d4be8 100644
--- a/guides/source/active_record_querying.md
+++ b/guides/source/active_record_querying.md
@@ -659,6 +659,40 @@ FROM orders
 GROUP BY date(created_at)
 ```
 
+### Total of grouped items
+
+To get the total of grouped items on a single query call `count` after the `group`.
+
+```ruby
+Order.group(:status).count
+# =>  { 'awaiting_approval' => 7, 'paid' => 12 }
+```
+
+The SQL that would be executed would be something like this:
+
+```sql
+SELECT COUNT (*) AS count_all, status AS status
+FROM "orders"
+GROUP BY status
+```
+
+It is possible to do this count with multiple values, to do this only add the
+other column to `group`.
+
+```ruby
+Order.group(:status, :delivery_method).count
+# =>  { ['awaiting_approval', 'regular'] => 5, ['awaiting_approval', 'fast'] => 2, ['paid', 'regular'] => 2, ['paid', 'fast'] => 10 }
+```
+
+The SQL that would be executed would be something like this:
+
+```sql
+SELECT COUNT (*) AS count_all, status AS status,
+delivery_method AS delivery_method
+FROM "orders"
+GROUP BY status, delivery_method
+```
+
 Having
 ------
 
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