Sql 使两列相加

我有一张桌子（苹果），里面有：

cid  date_am date_pm 
----------------------
1      1       1
2      2       1
3      1       3  
1      1       2

早些时候我问了一个问题（很糟糕），我将如何按照客户数量（1）对客户进行排名。解决方案是（基于一列）：

这对一列非常有效，但我如何对两列的总和进行同样的处理呢。 即

希望我能把这一点讲清楚，让你帮个忙-谢谢

select cid, sum(case when date_pm = 1 then 1 else 0 end) + sum(case when date_am = 1 then 1 else 0 end)
from apples
group by cid

或

---

多亏了这两个案例，你们给出的答案非常有效thanks@bsandrabr：如果某人在您投下向下一票后编辑了他们的答案，您可以通过单击向上一票箭头来反转向下一票。

SELECT cid, sum( date_pm ) AS No_of_ones
FROM apples
WHERE date_am =1
add to
SELECT cid, sum( date_am ) AS No_of_ones
FROM apples
WHERE date_pm =1
GROUP by cid
ORDER by no_of_ones(added)

select cid, sum(case when date_pm = 1 then 1 else 0 end) + sum(case when date_am = 1 then 1 else 0 end)
from apples
group by cid

select cid, sum(addone) as total from 
  (select cid, 1 as addone
   from apples
    where date_pm = 1 group by cid
    union
    select cid, 1 as addone
    from apples
    where date_am = 1 group by cid) 
group by cid order by total DESC

select cid, sum(case when date_am=1 then 1 else 0 end) 
            + sum(case when date_pm=1 then 1 else 0 end) as total 
from apples 
group by CID 
order by total DESC