SQL plus 2列數據內部計數

Question

我嘗試獲取結果3,5沒有計數重複，NUll值和空數據。

select count(distinct no1), count(distinct no1) + count(distinct no2) from abc where no1 
    is not null 

Answer 1

如果你不想空，空，試試這個：

select 
    count(distinct case when no1 = '' then null else no1 end), 
    count(distinct case when no1 = '' then null else no1 end) 
    + count(distinct case when no2 = '' then null else no2 end) 
from `tbl` 

見Demo在這裏。

解釋：count，sum，avg等等......像這些聚合函數不會採取null作爲其的測算對象。所以只需將空值設爲null，這裏使用case when來做到這一點，那麼count distinct就會得到你想要的。

Answer 2

select count(distinct no1), count(distinct no1) + (select count(distinct no2) from abc where no2 is not null and no2<>'') from abc where no1 is not null 

試試這個