計數和分組2列在一個表中

Question

這是我的表和數據

id | owner | buyer 
1 1  3 
2 2  2 
3 1  2 

我想要的結果是這樣

user | totals 
2  3 
1  2 
3  1 

用戶字段意味着業主和買家。 希望大家都明白。 謝謝〜

Answer 1

你可以做到這一點使用union all和group by：

select user, count(*) 
from ((select owner as user from t 
    ) union all 
     (select buyer from t 
    ) 
    ) ob 
group by user 
order by user;