From 7168dd09dd2eb2333046c91e043563146433494e Mon Sep 17 00:00:00 2001
From: scribu <scribu@git.wordpress.org>
Date: Mon, 6 Sep 2010 08:09:41 +0000
Subject: [PATCH] Rewrite WP_User_Query to use JOIN instead of subquery. See
 #14572

git-svn-id: https://develop.svn.wordpress.org/trunk@15579 602fd350-edb4-49c9-b593-d223f7449a82
---
 wp-includes/functions.php | 7 ++-----
 wp-includes/user.php      | 9 +++++----
 2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index f21fb6e66b..23f70f137f 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -4244,10 +4244,9 @@ function _wp_search_sql($string, $cols) {
  *
  * @param array $queries An array of queries
  * @param string $meta_id_column The column that holds the object id
- * @param string $table Which meta table to look in
  * @return string
  */
-function _wp_meta_sql( $queries, $meta_id_column, $table ) {
+function _wp_meta_sql( $queries, $meta_id_column ) {
 	global $wpdb;
 
 	$clauses = array();
@@ -4278,9 +4277,7 @@ function _wp_meta_sql( $queries, $meta_id_column, $table ) {
 		return '';
 
 	return "
-		SELECT $meta_id_column 
-		FROM $table 
-		WHERE CASE meta_key 
+		AND CASE meta_key 
 		" . implode( "\n", $clauses ) . "
 		END
 		GROUP BY $meta_id_column
diff --git a/wp-includes/user.php b/wp-includes/user.php
index b73c4f39e3..5dfce4ae17 100644
--- a/wp-includes/user.php
+++ b/wp-includes/user.php
@@ -463,10 +463,11 @@ class WP_User_Query {
 
 		$meta_queries[] = wp_array_slice_assoc( $qv, array( 'meta_key', 'meta_value', 'meta_compare' ) );
 
-		$meta_query_sql = _wp_meta_sql( $meta_queries, 'user_id', $wpdb->usermeta );
+		$meta_query_sql = _wp_meta_sql( $meta_queries, 'user_id' );
 
 		if ( !empty( $meta_query_sql ) ) {
-			$this->query_where .= " AND $wpdb->users.ID IN ($meta_query_sql)";
+			$this->query_from .= " INNER JOIN $wpdb->usermeta ON ($wpdb->users.ID = $wpdb->usermeta.user_id)";
+			$this->query_where .= $meta_query_sql;
 		}
 
 		if ( !empty($qv['include']) ) {
@@ -490,13 +491,13 @@ class WP_User_Query {
 	function query() {
 		global $wpdb;
 
-		$this->results = $wpdb->get_col("SELECT DISTINCT($wpdb->users.ID)" . $this->query_from . $this->query_where . $this->query_orderby . $this->query_limit);
+		$this->results = $wpdb->get_col("SELECT $wpdb->users.ID" . $this->query_from . $this->query_where . $this->query_orderby . $this->query_limit);
 
 		if ( !$this->results )
 			return;
 
 		if ( $this->query_vars['count_total'] )
-			$this->total_users = $wpdb->get_var("SELECT COUNT(DISTINCT($wpdb->users.ID))" . $this->query_from . $this->query_where);
+			$this->total_users = $wpdb->get_var("SELECT COUNT($wpdb->users.ID)" . $this->query_from . $this->query_where);
 
 		if ( 'all' == $this->query_vars['fields'] ) {
 			cache_users($this->results);