MySQL update select,update的同時select和for update語句

MySQL update select,update的同時select和for update語句   MySQL update && select   CREATE TABLE `testupdate` (   `id` bigint(20) NOT NULL AUTO_INCREMENT,   `val` bigint(20) NOT NULL DEFAULT '0',   PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8   update testupdate   set val = val+1   where id = 1 and @value := val+1;   select @value;