1. DATEDIFF()函数 语法：DATEDIFF(date1,date2) 例1：SELECT DATEDIFF('2015-09-22','2015-09-21') AS DiffDate //结果为 1例2：SELECT DATEDIFF('2015-09-20 17:34:44','2015-09-19 07:34:44') AS DiffDate

1. 在mybatis 中使用模糊查找 nickName like concat('%',#{nickName},'%') 2. 插入一个对象后返回他的id insert ignore into t_user ( mobile, password, register_time, last_login_time ) values ( #{mobile},