kotlin Smart cast to 'Int' is impossible, because 'xxx' is a mutable property that could have been changed by this time var xxx:Int?=null 声明了一个可能为空的整数xxx,这里的?号是将整数自动装箱为对象 当需要用到这个变量时,比如 xxx+5 就会报这个
Impossible WHERE noticed after reading const tables 阿里云反馈的慢SQL //sql如下select * from table where req_id ="123"; 执行计划返回如下: 而且该表的req_id创建了唯一索引:很明显,这个字段是保持幂等操作的,通过数据库的唯一索引实现; 每次数据落地前,都要执行该SQL查询是