行中非空值的计数

Question

有更好的方法吗？

select count(First)+count(id)+count(Last)+count(Telephone) 
from client 
where id ="1";

Answer 1

不确定这是否更好，但对于稍后阅读的人来说，意图可能会更清晰：

select 
  (case when First is null then 1 else 0 end) + 
  (case when id is null then 1 else 0 end) + 
  (case when Last is null then 1 else 0 end) + 
  (case when Telephone is null then 1 else 0 end) 
from client 
where id ="1";