Add example on using dot notation in related query.

Author: acinader

_includes/android/queries.md

@@ -152,6 +152,19 @@ losingUserQuery.findInBackground(new FindCallback<ParseUser>() {
   }
 });
 ```
+<p>To filter rows based on <code class="highlighter-rouge">objectId</code>’s from pointers in a second table, you can use dot notation:</p>
+
+```java
+ParseQuery<ParseObject> chartersOfTypeX = ParseQuery.getQuery("Charter");
+charterOfTypeX.equalTo('type', 'x');
+
+ParseQuery<ParseObject> groupsWithoutCharterX = ParseQuery.getQuery("Group");
+groupsWithoutCharterX.doesNotMatchKeyInQuery("objectId", "belongsTo.objectId", chartersOfTypeX);
+groupsWithoutCharterX.findInBackground(new FindCallback<ParseObject>() {
+  void done(List<ParseObject> results, ParseException e) {
+   // results has the list of groups without charter x
+ });
+```
 
 You can restrict the fields returned by calling `selectKeys` with a collection of keys. To retrieve documents that contain only the `score` and `playerName` fields (and also special built-in fields such as `objectId`, `createdAt`, and `updatedAt`):
 
@@ -365,7 +378,7 @@ final ParseQuery query = ...
 query.fromLocalDatastore().findInBackground().continueWithTask((task) -> {
   Exception error = task.getError();
   if (error instanceof ParseException && ((ParseException) error).getCode() == ParseException.CACHE_MISS) {
-    // No results from cache. Let's query the network.  
+    // No results from cache. Let's query the network.
     return query.fromNetwork().findInBackground();
   }
   return task;

_includes/js/queries.md

@@ -149,6 +149,19 @@ losingUserQuery.find({
 });
 </code></pre>
 
+To filter rows based on `objectId`'s from pointers in a second table, you can use dot notation:
+
+<pre><code class="javascript">
+const rolesOfTypeX = new Parse.Query('Role');
+rolesOfTypeX.equalTo('type', 'x');
+
+const groupsWithRoleX = new Parse.Query('Group');
+groupsWithRoleX.matchesKeyInQuery('objectId', 'belongsTo.objectId', rolesOfTypeX);
+groupsWithRoleX.find().then(function(results) {
+   // results has the list of groups with role x
+});
+</pre></code>
+
 You can restrict the fields returned by calling `select` with a list of keys. To retrieve documents that contain only the `score` and `playerName` fields (and also special built-in fields such as `objectId`, `createdAt`, and `updatedAt`):
 
 <pre><code class="javascript">

_includes/php/queries.md

@@ -139,6 +139,18 @@ $results = $losingUserQuery->find();
 // results has the array of users with a hometown team with a losing record
 </code></pre>
 
+To filter rows based on `objectId`'s from pointers in a second table, you can use dot notation:
+
+<pre><code class="php">
+$rolesOfTypeX = new ParseQuery('Role');
+$rolesOfTypeX->equalTo('type', 'x');
+
+$groupsWithRoleX = new ParseQuery('Group');
+$groupsWithRoleX->matchesKeyInQuery('objectId', 'belongsTo.objectId', rolesOfTypeX);
+$results = $groupsWithRoleX->find();
+// results has the list of groups with role x
+</pre></code>
+
 You can restrict the fields returned by calling `select` with an array of keys. To retrieve documents that contain only the `score` and `playerName` fields (and also special built-in fields such as `objectId`, `createdAt`, and `updatedAt`):
 
 <pre><code class="php">