. "LEFT JOIN `users` AS `u_t` ON `u_t`.`id` = `h`.`to`"пробел забыл,с ним
. "LEFT JOIN `users` AS `u_t` ON `u_t`.`id` = `h`.`to` "
. "LEFT JOIN `users` AS `u_t` ON `u_t`.`id` = `h`.`to`". "LEFT JOIN `users` AS `u_t` ON `u_t`.`id` = `h`.`to` "