From 0115ba2f30a98959dc8e53663f4cf7f808b10276 Mon Sep 17 00:00:00 2001
From: Scott Taylor <scott.c.taylor@mac.com>
Date: Mon, 24 Mar 2014 19:57:15 +0000
Subject: [PATCH] When using `meta_query` in a `WP_Query`, passing `NOT EXISTS`
 or `''` to `compare` should not require `value` to be set. The resulting SQL
 should then produce the appropriate `OR` clause for existence of
 non-existence after passing the query to the `$key_only_queries` stack
 internally.

Adds unit tests.

Props chrisguitarguy, for the original patch.
Fixes #23268.


Built from https://develop.svn.wordpress.org/trunk@27689


git-svn-id: http://core.svn.wordpress.org/trunk@27528 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/meta.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/wp-includes/meta.php b/wp-includes/meta.php
index dc19833612..b3a06c9681 100644
--- a/wp-includes/meta.php
+++ b/wp-includes/meta.php
@@ -753,7 +753,7 @@ class WP_Meta_Query {
 		// Split out the meta_key only queries (we can only do this for OR)
 		if ( 'OR' == $this->relation ) {
 			foreach ( $this->queries as $k => $q ) {
-				if ( ! array_key_exists( 'value', $q ) && ! empty( $q['key'] ) )
+				if ( ( empty( $q['compare'] ) || 'NOT EXISTS' != $q['compare'] ) && ! array_key_exists( 'value', $q ) && ! empty( $q['key'] ) )
 					$key_only_queries[$k] = $q;
 				else
 					$queries[$k] = $q;