Ticket #19729: meta.diff

wp-includes/meta.php

@@ -707 +707 @@
                 $join = array();
                 $where = array();
 
+                $key_only_queries = array();
+                $queries = array();
+                
+                // Split out the meta_key only queries (we can only do this for OR)
                 foreach ( $this->queries as $k => $q ) {
+                        if ( $this->relation == 'OR' && ! isset( $q['value'] ) && ! empty( $q['key'] ) )
+                                $key_only_queries[$k] = $q;
+                        
+                        else
+                                $queries[$k] = $q;
+                }
+                
+                // Specify all the meta_key only queries in one go
+                if ( $key_only_queries ) {
+                        $join[]  = "INNER JOIN $meta_table ON $primary_table.$primary_id_column = $meta_table.$meta_id_column";
+                        
+                        foreach ( $key_only_queries as $key => $q )
+                                $where["key-only-$key"] = $wpdb->prepare( "$meta_table.meta_key = %s", trim( $q['key'] ) );
+                }
+                                                
+                foreach ( $queries as $k => $q ) {
                         $meta_key = isset( $q['key'] ) ? trim( $q['key'] ) : '';
                         $meta_type = isset( $q['type'] ) ? strtoupper( $q['type'] ) : 'CHAR';