From d328751ee7f63ba8641ff4c995e97cd720268b93 Mon Sep 17 00:00:00 2001
From: Ryan Boren <ryan@git.wordpress.org>
Date: Thu, 21 Apr 2011 18:13:03 +0000
Subject: [PATCH] Allow querying empty meta values. Props scribu. fixes #15292

git-svn-id: https://develop.svn.wordpress.org/trunk@17674 602fd350-edb4-49c9-b593-d223f7449a82
---
 wp-includes/meta.php | 21 ++++++++++++---------
 wp-includes/user.php |  2 +-
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/wp-includes/meta.php b/wp-includes/meta.php
index 27a1288187..e059b280fe 100644
--- a/wp-includes/meta.php
+++ b/wp-includes/meta.php
@@ -387,7 +387,6 @@ function _get_meta_sql( $meta_query, $type, $primary_table, $primary_id_column,
 	$i = 0;
 	foreach ( $meta_query as $q ) {
 		$meta_key = isset( $q['key'] ) ? trim( $q['key'] ) : '';
-		$meta_value = isset( $q['value'] ) ? $q['value'] : '';
 		$meta_compare = isset( $q['compare'] ) ? strtoupper( $q['compare'] ) : '=';
 		$meta_type = isset( $q['type'] ) ? strtoupper( $q['type'] ) : 'CHAR';
 
@@ -413,16 +412,20 @@ function _get_meta_sql( $meta_query, $type, $primary_table, $primary_id_column,
 		if ( !empty( $meta_key ) )
 			$where .= $wpdb->prepare( " AND $alias.meta_key = %s", $meta_key );
 
+		if ( !isset( $q['value'] ) )
+			continue;
+		$meta_value = $q['value'];
+
 		if ( in_array( $meta_compare, array( 'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN' ) ) ) {
 			if ( ! is_array( $meta_value ) )
 				$meta_value = preg_split( '/[,\s]+/', $meta_value );
+
+			if ( empty( $meta_value ) )
+				continue;
 		} else {
 			$meta_value = trim( $meta_value );
 		}
 
-		if ( empty( $meta_value ) )
-			continue;
-
 		if ( 'IN' == substr( $meta_compare, -2) ) {
 			$meta_compare_string = '(' . substr( str_repeat( ',%s', count( $meta_value ) ), 1 ) . ')';
 		} elseif ( 'BETWEEN' == substr( $meta_compare, -7) ) {
@@ -435,10 +438,6 @@ function _get_meta_sql( $meta_query, $type, $primary_table, $primary_id_column,
 			$meta_compare_string = '%s';
 		}
 
-		// @todo Temporary hack to support empty values. Do not use outside of core.
-		if ( '_wp_zero_value' == $meta_value )
-			$meta_value = 0;
-
 		$where .= $wpdb->prepare( " AND CAST($alias.meta_value AS {$meta_type}) {$meta_compare} {$meta_compare_string}", $meta_value );
 	}
 
@@ -457,11 +456,15 @@ function _parse_meta_query( &$qv ) {
 	$meta_query = array();
 
 	// Simple query needs to be first for orderby=meta_value to work correctly
-	foreach ( array( 'key', 'value', 'compare', 'type' ) as $key ) {
+	foreach ( array( 'key', 'compare', 'type' ) as $key ) {
 		if ( !empty( $qv[ "meta_$key" ] ) )
 			$meta_query[0][ $key ] = $qv[ "meta_$key" ];
 	}
 
+	// WP_Query sets 'meta_value' = '' by default
+	if ( isset( $qv[ 'meta_value' ] ) && '' !== $qv[ 'meta_value' ] )
+		$meta_query[0]['value'] = $qv[ 'meta_value' ];
+
 	if ( !empty( $qv['meta_query'] ) && is_array( $qv['meta_query'] ) ) {
 		$meta_query = array_merge( $meta_query, $qv['meta_query'] );
 	}
diff --git a/wp-includes/user.php b/wp-includes/user.php
index 0a1a4354ac..862d712d8e 100644
--- a/wp-includes/user.php
+++ b/wp-includes/user.php
@@ -496,7 +496,7 @@ class WP_User_Query {
 
 		if ( 'authors' == $qv['who'] && $blog_id ) {
 			$qv['meta_key'] = $wpdb->get_blog_prefix( $blog_id ) . 'user_level';
-			$qv['meta_value'] = '_wp_zero_value'; // Hack to pass '0'
+			$qv['meta_value'] = 0;
 			$qv['meta_compare'] = '!=';
 			$qv['blog_id'] = $blog_id = 0; // Prevent extra meta query
 		}