根據多列中存在的ID總結髮票金額

Question

假設我有一張表，其中包含按行和6列的發票行，其中員工ID可以標記爲該發票。員工ID不能連續複製，但不同列的不同發票行可以存在相同的員工ID。在下面的表中，REP 1應具有我希望能夠總結由僱員ID的總量的500

總量（REP 1，REP 2，等等。）。我可以通過一個大型的聯合查詢來做到這一點，但問題是我有一個我需要總結的大約450個員工ID的列表。有沒有辦法讓我有一個查詢吐出一張員工ID和他們的總金額列表？

Answer 1

我會建議使用cross apply：

select v.e, sum(t.amount) 
from t cross apply 
    (values (slot1), (slot2), (slot3), (slot4), (slot5), (slot6)) v(e) 
group by v.e; 

注：這是假設您正在使用SQL Server。

Answer 2

連接表是一種方式......

select e.employee_id, 
     sum(i.amount) 
    from invoice i, 
    join employee e on (e.employee_id in (i.slot1, i.slot2, i.slot3, i.slot4, i.slot5, i.slot6)) 
group by e.employee_id; 

的另一種方式......

select employee_id, 
     sum(amount) 
from (
    select slot1 employee_id, sum(amount) amount from invoice group by slot1 union 
    select slot2, sum(amount) from invoice group by slot2 union all 
    select slot3, sum(amount) from invoice group by slot3 union all 
    select slot4, sum(amount) from invoice group by slot4 union all 
    select slot5, sum(amount) from invoice group by slot5 union all 
    select slot6, sum(amount) from invoice group by slot6 
) as q1 
group by employee_id;