Ticket #11649: 11649-distinct .patch

wp-admin/includes/upgrade.php

@@ -1688 +1688 @@
         // Upgrade versions prior to 2.9
         if ( $wp_current_db_version < 11557 ) {
                 // Delete duplicate options.  Keep the option with the highest option_id.
-                $delete_options = $wpdb->get_col("SELECT o1.option_id FROM $wpdb->options AS o1 JOIN $wpdb->options AS o2 ON o2.option_name = o1.option_name AND o2.option_id > o1.option_id");
+                $delete_options = $wpdb->get_col("SELECT DISTINCT o1.option_id FROM $wpdb->options AS o1 JOIN $wpdb->options AS o2 ON o2.option_name = o1.option_name AND o2.option_id > o1.option_id");
                 if ( !empty($delete_options) ) {
                         $delete_options = implode(',', $delete_options);
                         $wpdb->query("DELETE FROM $wpdb->options WHERE option_id IN ($delete_options)");