java - mysql语句把满足某一条件的结果放到查询结果的最后面怎么弄

Question

订单列表
订单列表中有没有设置服务时间的,有已经设置过服务时间的,现在需要查询订单,按订单的服务时间升序排列,但是要把没有设置服务时间(默认为1970年)放到最后面,用一个sql语句怎么解决呢?

Answer 1

MySQL:
select * from t order by IF(ISNULL(order_col),1,0), order_col asc;

Oracle
select * from t order by order_col asc nulls last;  

Answer 2

Use Union to merge query results.
(select * from a where service_time = !null order by service_time asc)
union
(select * from a where service_time = null);

Where post-condition can be modified accordingly according to your specific service_time default value.