Fix generated query in Retrieving specific data from multiple tables …

…section [ci skip]

guides/source/active_record_querying.md

@@ -1547,7 +1547,7 @@ SELECT people.id, people.name, comments.text
 FROM people
 INNER JOIN comments
   ON comments.person_id = people.id
-WHERE comments.created_at = '2015-01-01'
+WHERE comments.created_at > '2015-01-01'
 ```
 
 ### Retrieving specific data from multiple tables