PHPORM-286 Add Query::countByGroup and other aggregateByGroup functions

Author: GromNaN

src/Query/Builder.php

@@ -30,6 +30,7 @@
 use Override;
 use RuntimeException;
 use stdClass;
+use TypeError;
 
 use function array_fill_keys;
 use function array_filter;
@@ -324,8 +325,10 @@ public function toMql(): array
                     // this mimics SQL's behaviour a bit.
                     $group[$column] = ['$last' => '$' . $column];
                 }
+            }
 
-                // Do the same for other columns that are selected.
+            // Add the last value of each column when there is no aggregate function.
+            if ($this->groups && ! $this->aggregate) {
                 foreach ($columns as $column) {
                     $key = str_replace('.', '_', $column);
 
@@ -349,7 +352,7 @@ public function toMql(): array
 
                     $aggregations = blank($this->aggregate['columns']) ? [] : $this->aggregate['columns'];
 
-                    if (in_array('*', $aggregations) && $function === 'count') {
+                    if (in_array('*', $aggregations) && $function === 'count' && empty($group['_id'])) {
                         $options = $this->inheritConnectionOptions($this->options);
 
                         return ['countDocuments' => [$wheres, $options]];
@@ -559,6 +562,8 @@ public function generateCacheKey()
     /** @return ($function is null ? AggregationBuilder : mixed) */
     public function aggregate($function = null, $columns = ['*'])
     {
+        assert(is_array($columns), new TypeError(sprintf('Argument #2 ($columns) must be of type array, %s given', get_debug_type($columns))));
+
         if ($function === null) {
             if (! trait_exists(FluentFactoryTrait::class)) {
                 // This error will be unreachable when the mongodb/builder package will be merged into mongodb/mongodb
@@ -599,13 +604,32 @@ public function aggregate($function = null, $columns = ['*'])
         $this->columns            = $previousColumns;
         $this->bindings['select'] = $previousSelectBindings;
 
+        // When the aggregation is per group, we return the results as is.
+        if ($this->groups) {
+            return $results->map(function (object $result) {
+                unset($result->id);
+
+                return $result;
+            });
+        }
+
         if (isset($results[0])) {
             $result = (array) $results[0];
 
             return $result['aggregate'];
         }
     }
 
+    /**
+     * {@inheritDoc}
+     *
+     * @see \Illuminate\Database\Query\Builder::aggregateByGroup()
+     */
+    public function aggregateByGroup(string $function, array $columns = ['*'])
+    {
+        return $this->aggregate($function, $columns);
+    }
+
     /** @inheritdoc */
     public function exists()
     {

tests/QueryBuilderTest.php

@@ -7,6 +7,7 @@
 use Carbon\Carbon;
 use DateTime;
 use DateTimeImmutable;
+use Illuminate\Support\Collection as LaravelCollection;
 use Illuminate\Support\Facades\Date;
 use Illuminate\Support\Facades\DB;
 use Illuminate\Support\LazyCollection;
@@ -617,6 +618,35 @@ public function testSubdocumentArrayAggregate()
         $this->assertEquals(12, DB::table('items')->avg('amount.*.hidden'));
     }
 
+    public function testAggregateGroupBy()
+    {
+        DB::table('users')->insert([
+            ['name' => 'John Doe', 'role' => 'admin', 'score' => 1],
+            ['name' => 'Jane Doe', 'role' => 'admin', 'score' => 2],
+            ['name' => 'Robert Roe', 'role' => 'user', 'score' => 4],
+        ]);
+
+        $results = DB::table('users')->groupBy('role')->orderBy('role')->countByGroup();
+        $this->assertInstanceOf(LaravelCollection::class, $results);
+        $this->assertEquals([(object) ['role' => 'admin', 'aggregate' => 2], (object) ['role' => 'user', 'aggregate' => 1]], $results->toArray());
+
+        $results = DB::table('users')->groupBy('role')->orderBy('role')->maxByGroup('score');
+        $this->assertInstanceOf(LaravelCollection::class, $results);
+        $this->assertEquals([(object) ['role' => 'admin', 'aggregate' => 2], (object) ['role' => 'user', 'aggregate' => 4]], $results->toArray());
+
+        $results = DB::table('users')->groupBy('role')->orderBy('role')->minByGroup('score');
+        $this->assertInstanceOf(LaravelCollection::class, $results);
+        $this->assertEquals([(object) ['role' => 'admin', 'aggregate' => 1], (object) ['role' => 'user', 'aggregate' => 4]], $results->toArray());
+
+        $results = DB::table('users')->groupBy('role')->orderBy('role')->sumByGroup('score');
+        $this->assertInstanceOf(LaravelCollection::class, $results);
+        $this->assertEquals([(object) ['role' => 'admin', 'aggregate' => 3], (object) ['role' => 'user', 'aggregate' => 4]], $results->toArray());
+
+        $results = DB::table('users')->groupBy('role')->orderBy('role')->avgByGroup('score');
+        $this->assertInstanceOf(LaravelCollection::class, $results);
+        $this->assertEquals([(object) ['role' => 'admin', 'aggregate' => 1.5], (object) ['role' => 'user', 'aggregate' => 4]], $results->toArray());
+    }
+
     public function testUpdateWithUpsert()
     {
         DB::table('items')->where('name', 'knife')