Timber\Cache\Cleaner::delete_transients_multisite PHP Метод

    protected static function delete_transients_multisite()
    {
        global $wpdb;
        $sql = "\n\t\t\t\t\tDELETE\n\t\t\t\t\t\ta, b\n\t\t\t\t\tFROM\n\t\t\t\t\t\t{$wpdb->sitemeta} a, {$wpdb->sitemeta} b\n\t\t\t\t\tWHERE\n\t\t\t\t\t\ta.meta_key LIKE '_site_transient_%' AND\n\t\t\t\t\t\ta.meta_key NOT LIKE '_site_transient_timeout_%' AND\n\t\t\t\t\t\tb.meta_key = CONCAT(\n\t\t\t\t\t\t\t'_site_transient_timeout_',\n\t\t\t\t\t\t\tSUBSTRING(\n\t\t\t\t\t\t\t\ta.meta_key,\n\t\t\t\t\t\t\t\tCHAR_LENGTH('_site_transient_') + 1\n\t\t\t\t\t\t\t)\n\t\t\t\t\t\t)\n\t\t\t\t\tAND b.meta_value < UNIX_TIMESTAMP()\n\t\t\t\t";
        $clean = $wpdb->query($sql);
        return $clean;
    }