[5.2] Add relationship subquery count

src/Illuminate/Database/Eloquent/Builder.php

@@ -999,6 +999,41 @@ public function with($relations)
         return $this;
     }
 
+    /**
+     * Add subselect queries to count the relations.
+     *
+     * @param  mixed  $relations
+     * @return $this
+     */
+    public function withCount($relations)
+    {
+        // If no columns are set, add the default * columns.
+        if (is_null($this->query->columns)) {
+            $this->query->select(['*']);
+        }
+
+        if (is_string($relations)) {
+            $relations = func_get_args();
+        }
+
+        $relations = $this->parseWithRelations($relations);
+
+        foreach ($relations as $name => $constraints) {
+            // First determine the count query for the given relationship,
+            // then run the constraints callback to get the final query.
+            // This query will be added as subSelect query.
+            $relation = $this->getHasRelationQuery($name);
+            $query = $relation->getRelationCountQuery($relation->getRelated()->newQuery(), $this);
+
+            call_user_func($constraints, $query);
+
+            $asColumn = snake_case($name).'_count';
+            $this->selectSub($query->getQuery(), $asColumn);
+        }
+
+        return $this;
+    }
+
     /**
      * Parse a list of relations into individuals.
      *

tests/Database/DatabaseEloquentBuilderTest.php

@@ -455,6 +455,37 @@ public function testDeleteOverride()
         $this->assertEquals(['foo' => $builder], $builder->delete());
     }
 
+    public function testWithCount()
+    {
+        $model = new EloquentBuilderTestModelParentStub;
+
+        $builder = $model->withCount('foo');
+
+        $this->assertEquals('select *, (select count(*) from "eloquent_builder_test_model_close_related_stubs" where "eloquent_builder_test_model_parent_stubs"."foo_id" = "eloquent_builder_test_model_close_related_stubs"."id") as "foo_count" from "eloquent_builder_test_model_parent_stubs"', $builder->toSql());
+    }
+
+    public function testWithCountAndSelect()
+    {
+        $model = new EloquentBuilderTestModelParentStub;
+
+        $builder = $model->select('id')->withCount('foo');
+
+        $this->assertEquals('select "id", (select count(*) from "eloquent_builder_test_model_close_related_stubs" where "eloquent_builder_test_model_parent_stubs"."foo_id" = "eloquent_builder_test_model_close_related_stubs"."id") as "foo_count" from "eloquent_builder_test_model_parent_stubs"', $builder->toSql());
+    }
+
+    public function testWithCountAndContraintsAndHaving()
+    {
+        $model = new EloquentBuilderTestModelParentStub;
+
+        $builder = $model->where('bar', 'baz');
+        $builder->withCount(['foo' => function ($q) {
+            $q->where('bam', '>', 'qux');
+        }])->having('fooCount', '>=', 1);
+
+        $this->assertEquals('select *, (select count(*) from "eloquent_builder_test_model_close_related_stubs" where "eloquent_builder_test_model_parent_stubs"."foo_id" = "eloquent_builder_test_model_close_related_stubs"."id" and "bam" > ?) as "foo_count" from "eloquent_builder_test_model_parent_stubs" where "bar" = ? having "fooCount" >= ?', $builder->toSql());
+        $this->assertEquals(['qux', 'baz', 1], $builder->getBindings());
+    }
+
     public function testHasWithContraintsAndHavingInSubquery()
     {
         $model = new EloquentBuilderTestModelParentStub;