Index: trunk/wp-includes/meta.php
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- trunk/wp-includes/meta.php	(revision 21609)
+++ trunk/wp-includes/meta.php	(revision )
@@ -636,6 +636,14 @@
 	public $relation;
 
 	/**
+	 * The relation between the meta query and what it's pulled into. Can be one of 'AND' or 'OR'.
+	 *
+	 * @access public
+	 * @var string
+	 */
+	public $query_relation;
+
+	/**
 	 * Constructor
 	 *
 	 * @param array $meta_query (optional) A meta query
@@ -650,6 +658,13 @@
 			$this->relation = 'AND';
 		}
 
+		if ( isset( $meta_query[ 'query_relation' ] ) && strtoupper( $meta_query[ 'query_relation' ] ) == 'OR' ) {
+			$this->query_relation = 'OR';
+		}
+		else {
+			$this->query_relation = 'AND';
+		}
+
 		$this->queries = array();
 
 		foreach ( $meta_query as $key => $query ) {
@@ -798,7 +813,7 @@
 		if ( empty( $where ) )
 			$where = '';
 		else
-			$where = ' AND (' . implode( "\n{$this->relation} ", $where ) . ' )';
+			$where = " {$this->query_relation} (" . implode( "\n{$this->relation} ", $where ) . ' )';
 
 		$join = implode( "\n", $join );
 		if ( ! empty( $join ) )