Ticket #11398: 11398.2.diff

tests/tests/query/results.php

@@ -369 +369 @@
                         'child-two',
                 ), wp_list_pluck( $posts, 'post_title' ) );
         }
+
+        /**
+         * @ticket 11398
+         */
+        function test_query_orderby_comment_date() {
+                $post_date = '2013-08-02 14:15:04';
+                $one = $this->factory->post->create( array( 'post_title' => 'one', 'post_date' => $post_date ) );
+                $two = $this->factory->post->create( array( 'post_title' => 'two', 'post_date' => $post_date ) );
+                $three = $this->factory->post->create( array( 'post_title' => 'three', 'post_date' => $post_date ) );
+                $four = $this->factory->post->create( array( 'post_title' => 'four', 'post_date' => $post_date ) );
+
+                $this->factory->comment->create_post_comments( $three, 1, array( 'comment_date' => '2013-08-02 14:15:05' ) );
+                $this->factory->comment->create_post_comments( $two, 1, array( 'comment_date' => '2013-08-02 14:15:06' ) );
+                $this->factory->comment->create_post_comments( $one, 1, array( 'comment_date' => '2013-08-02 14:15:07' ) );
+
+                $asc_posts = $this->q->query( array(
+                        'post__in' => array( $one, $two, $three, $four ),
+                        'orderby' => 'comment_date',
+                        'order' => 'ASC'
+                ) );
+
+                $this->assertEquals( array(
+                        'three',
+                        'two',
+                        'one',
+                        'four',
+                ), wp_list_pluck( $asc_posts, 'post_title' ) );
+
+                $desc_posts = $this->q->query( array(
+                        'post__in' => array( $one, $two, $three, $four ),
+                        'orderby' => 'comment_date',
+                        'order' => 'DESC'
+                ) );
+
+                $this->assertEquals( array(
+                        'one',
+                        'two',
+                        'three',
+                        'four',
+                ), wp_list_pluck( $desc_posts, 'post_title' ) );
+        }
 }

src/wp-includes/query.php

@@ -2361 +2361 @@
                         $orderby = "FIELD( {$wpdb->posts}.post_parent, $post_parent__in )";
                 } else {
                         // Used to filter values
-                        $allowed_keys = array('name', 'author', 'date', 'title', 'modified', 'menu_order', 'parent', 'ID', 'rand', 'comment_count');
+                        $allowed_keys = array( 'name', 'author', 'date', 'title', 'modified', 'menu_order', 'parent', 'ID', 'rand', 'comment_count', 'comment_date' );
                         if ( !empty($q['meta_key']) ) {
                                 $allowed_keys[] = $q['meta_key'];
                                 $allowed_keys[] = 'meta_value';
@@ -2396 +2396 @@
                                         case 'comment_count':
                                                 $orderby = "$wpdb->posts.comment_count";
                                                 break;
+                                        case 'comment_date':
+                                                $orderby = "ISNULL($wpdb->comments.comment_date), $wpdb->comments.comment_date";
+                                                $join .= " LEFT JOIN $wpdb->comments ON $wpdb->posts.ID = $wpdb->comments.comment_post_ID ";
+                                                break;
                                         default:
                                                 $orderby = "$wpdb->posts.post_" . $orderby;
                                 }