在SQL中连接表上的两列

Question

我有一个很容易理解的问题,但对我而言,实现并不是那么简单.

我有一个名为Time的表:

-----------------------------------
 DAY     TIME1     TIME2
-----------------------------------
 1       08.00     09.40
 1       09.40     10.00
 1       10.00     11.40
 2       08.00     08.50
 2       08.50     10.40
 ----------------------------------

我想得到的是:

-------------------
 DAY     TIME     
-------------------
 1       08.00     
 1       09.40     
 1       10.00     
 1       11.00     
 2       08.00     
 2       08.50     
 2       10.40     
 ------------------

我试过这段代码:

SELECT DISTINCT sub.val FROM (
  SELECT Time1 AS val FROM Time
  UNION ALL
  SELECT Time2 AS val FROM Time
) AS sub

它只返回时间列.我不知道加入"日"专栏.当我试图在"DISTINCT sub.val"之后添加"Day "时,它出错了.怎么做？

非常感谢你.

Answer 1

select distinct day, time1 from mytab
union
select distinct day, time2 from mytab