与 sum 一起时的情况

Question

有一个名为 workers comp 的额外付款人，我正在尝试通过 case when 语句将其作为 Workers Comp/Liability。我正在尝试 return 一行一行。非常感谢您的帮助。

这是我的查询：

select distinct
    case when payer.class like 'Workers%' 
        then 'Workers Comp/Liability'
        else Payer.class
    end as Payer,
    sum(Payment.payment_at) AS SumOfPmt
from Payer inner join Payer.payerid = Payment.payerid 
where payer.class like 'Workers%'
Group By payer.class

结果：

Payer | SumOfPmt Workers Comp/Liability | 558.76 Workers Comp/Liability | 167036.41

我想要的：

Payer | SumOfPmt Workers Comp/Liability | 167595.17

Answer 1

我会用 GROUP BY 子句重复相同的 CASE 表达式：

select (case when p.class like 'Workers%' 
             then 'Workers Comp/Liability'
             else p.class
        end) as Payer,
       sum(pay.payment_at) AS SumOfPmt
from Payer p inner join 
     Payment py
     on p.payerid = py.payerid 
where p.class like 'Workers%'
group by (case when p.class like 'Workers%' 
               then 'Workers Comp/Liability'
               else p.class
          end);

您不需要使用 DISTINCT，因为它有 GROUP BY。

Answer 2

这将是您查询的一种更简单的形式：

select 'Workers Comp/Liability' as Payer,
       sum(pm.payment_at) AS SumOfPmt
from Payer py inner join
     Payment pm
     on py.payerid = pm.payerid 
where py.class like 'Workers%';

您的 WHERE 子句和 CASE 表达式做同样的事情。只需要一个。

与 sum 一起时的情况

Case when along with sum

sql

oracle

max

case-when