diff --git a/wp-admin/includes/class-wp-users-list-table.php b/wp-admin/includes/class-wp-users-list-table.php
index f264fa243..68ced7c78 100644
--- a/wp-admin/includes/class-wp-users-list-table.php
+++ b/wp-admin/includes/class-wp-users-list-table.php
@@ -169,7 +169,6 @@ class WP_Users_List_Table extends WP_List_Table {
 			'username' => 'login',
 			'name'     => 'name',
 			'email'    => 'email',
-			'posts'    => 'post_count',
 		);
 
 		if ( $this->is_site_users )
diff --git a/wp-includes/user.php b/wp-includes/user.php
index 042fc9151..d08c95713 100644
--- a/wp-includes/user.php
+++ b/wp-includes/user.php
@@ -431,6 +431,7 @@ class WP_User_Query {
 		} elseif ( 'name' == $qv['orderby'] || 'display_name' == $qv['orderby'] ) {
 			$orderby = 'display_name';
 		} elseif ( 'post_count' == $qv['orderby'] ) {
+			// todo: avoid the JOIN
 			$where = get_posts_by_author_sql('post');
 			$this->query_from .= " LEFT OUTER JOIN (
 				SELECT post_author, COUNT(*) as post_count