select * from `messages` where ((`to` = ? and `from` = ? and `recipient_type` = ? and `timer` is null)) or ((`to` = ? and `from` = ? and `recipient_type` = ? and `timer` is null)) and not exists (select * from `message_deletes` where `messages`.`mid` = `message_deletes`.`message_id` and `user_id` = ?) order by `id` desc limit 100