Ticket #28439: 28439.2.patch

wp-includes/taxonomy.php

@@ -1385 +1385 @@
                 $orderby = 't.slug';
         } else if ( 'term_group' == $_orderby ) {
                 $orderby = 't.term_group';
+        } else if ( 'post_date' == $_orderby ) {
+                $orderby = 'p.post_date';
         } else if ( 'none' == $_orderby ) {
                 $orderby = '';
         } elseif ( empty($_orderby) || 'id' == $_orderby ) {
@@ -1561 +1563 @@
 
         $join = "INNER JOIN $wpdb->term_taxonomy AS tt ON t.term_id = tt.term_id";
 
+        // if we're ordering by date, we need to SELECT DISTINCT and JOIN term_relationships and posts
+        if ( 'post_date' == $_orderby ) {
+                $fields = "DISTINCT " . $fields;
+                // JOIN with wp_term_relationships
+                $join .= " JOIN $wpdb->term_relationships AS tr ON tr.term_taxonomy_id = tt.term_taxonomy_id";
+                // JOIN with wp_posts
+                $join .= " JOIN $wpdb->posts AS p ON p.ID = tr.object_id";
+        }
+
         $pieces = array( 'fields', 'join', 'where', 'orderby', 'order', 'limits' );
 
         /**