DOCSP-35972: Distinct values usage example

docs/includes/usage-examples/DistinctTest.php

@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Http\Controllers;
+
+use App\Models\Movie;
+use MongoDB\Laravel\Tests\TestCase;
+
+class DistinctTest extends TestCase
+{
+    /**
+     * @runInSeparateProcess
+     * @preserveGlobalState disabled
+     */
+    public function testDistinct(): void
+    {
+        require_once __DIR__ . '/Movie.php';
+
+        Movie::truncate();
+        Movie::insert([
+            [
+                'title' => 'The Big House',
+                'imdb' => [
+                    'rating' => 7.3,
+                    'votes' => 1161,
+                ],
+            ],
+            [
+                'title' => 'The Divorcee',
+                'imdb' => [
+                    'rating' => 6.9,
+                    'votes' => 1740,
+                ],
+            ],
+            [
+                'title' => 'Morocco',
+                'imdb' => [
+                    'rating' => 7.3,
+                    'votes' => 3566,
+                ],
+            ],
+        ]);
+
+        // begin-distinct
+        $ratings = Movie::where('year', 1930)
+            ->select('imdb.rating')
+            ->distinct()
+            ->get();
+
+        echo $ratings;
+        // end-distinct
+
+        $this->expectOutputString('[[6.9],[7.3]]');
+    }
+}

docs/usage-examples.txt

@@ -74,3 +74,4 @@ calls the controller function and returns the result to a web interface.
    /usage-examples/findOne
    /usage-examples/updateOne
    /usage-examples/deleteOne
+   /usage-examples/distinct

docs/usage-examples/distinct.txt

@@ -0,0 +1,67 @@
+.. _laravel-distinct-usage:
+
+==============================
+Retrieve Distinct Field Values
+==============================
+
+.. facet::
+   :name: genre
+   :values: reference
+
+.. meta::
+   :keywords: unique, different, code example
+
+.. contents:: On this page
+   :local:
+   :backlinks: none
+   :depth: 1
+   :class: singlecol
+
+You can retrieve distinct field values of documents in a collection by calling the ``distinct()``
+method on an object collection or a query builder.
+
+To retrieve distinct field values, pass a query filter to the ``where()`` method and a field name
+to the ``select()`` method. Then, call ``distinct()`` to return the unique field values of documents
+that match the query filter.
+
+Example
+-------
+
+This usage example performs the following actions:
+
+- Uses the ``Movie`` Eloquent model to represent the ``movies`` collection in the
+  ``sample_mflix`` database
+- Retrieves distinct field values of documents from the ``movies`` collection that match a query filter
+- Prints the distinct values
+
+The example calls the following methods on the ``Movie`` model:
+
+- ``where()``: matches documents in which the value of the ``year`` field is ``1930``.
+- ``select()``: retrieves the matching documents' ``imdb.rating`` field values.
+- ``distinct()``: accesses the unique values of the ``imdb.rating`` field for each matching
+  document. This method returns a list of values.
+- ``get()``: retrieves the query results.
+
+.. io-code-block::
+   :copyable: true
+
+   .. input:: ../includes/usage-examples/DistinctTest.php
+      :start-after: begin-distinct
+      :end-before: end-distinct
+      :language: php
+      :dedent:
+
+   .. output::
+      :language: console
+      :visible: false
+
+      [[5.8],[6],[6.7],[6.9],[7.2],[7.3],[7.5]]
+
+To learn how to edit your Laravel application to run the usage example, see the
+:ref:`Usage Examples landing page <laravel-usage-examples>`.
+
+.. tip::
+
+   For more information about query filters, see the :ref:`laravel-retrieve-matching` section of
+   the Read Operations guide.
+