Add Select Values For SQL Counts as a rails til.

README.md

@@ -89,6 +89,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 - [Creating Records of Has_One Associations](rails/creating-records-of-has-one-associations.md)
 - [Pretend Generations](rails/pretend-generations.md)
 - [Retrieve An Object If It Exists](rails/retrieve-an-object-if-it-exists.md)
+- [Select Value For SQL Counts](rails/select-values-for-sql-counts.md)
 - [Show Pending Migrations](rails/show-pending-migrations.md)
 
 ### ruby

rails/select-value-for-sql-counts.md

@@ -0,0 +1,14 @@
+# Select Value For SQL Counts
+
+If you are like me and prefer writing raw SQL over the Arel DSL for counting
+stuff in your database, then the `select_value` method will come in handy.
+Write a command similar to the following with a type cast to get the count
+of _whatever_.
+
+```ruby
+> sql = 'select count(*) from posts where published_at is not null'
+=> "select count(*) from posts where published_at is not null"
+> ActiveRecord::Base.connection.select_value(sql).to_i
+   (0.6ms)  select count(*) from posts where published_at is not null
+=> 42
+```