hive 计算年龄
--effective_date 可以是当前日期,也可以是数据中中数据的创建日期
--计算年龄 , if( datediff(ui.effective_date , CONCAT(substr(ui.effective_date , 0, 4), substr(uip.user_birthday, 5, 7)))>=0, (substr(ui.effective_date , 0, 4) - substr(uip.user_birthday, 0, 4)), (substr(ui.effective_date , 0, 4) - substr(uip.user_birthday, 0, 4) - 1) ) as uip_user_age