Question

我有一个查询，我使用SUM来计算帐单明细值。我想创建一个CASE语句来处理该总和的结果，而不是求和的值。以下是我的查询目前的部分示例。

SELECT 
    bill.billnumber_id, 
    billdetail.billclass, 
    SUM(billdetail.amount) AS Amount
GROUP BY bill.billnumber_id, billdetail.billclass

假设这总计4行billdetail（2,0,5,3），总和为10.我想根据10个数量做CASE语句，而不是个人价值观。感谢。

Answer 1

这是你想要的吗？

SELECT bill.billnumber_id, billdetail.billclass, SUM(billdetail.amount) AS Amount,
       (case when SUM(billdetail.amount) > 10 then 'BigOne'
             else 'Little'
        end)
GROUP BY bill.billnumber_id, billdetail.billclass

Answer 2

您需要使用子查询：

SELECT CASE WHEN Amount = 0 THEN 'Nothing' ELSE 'somthing' END AmountComment
FROM(
  SELECT bill.billnumber_id, billdetail.billclass, SUM(billdetail.amount) AS Amount
  GROUP BY bill.billnumber_id, billdetail.billclass
)x

Answer 3

您可以将其设为子查询：

SELECT billnumber_id, billclass, CASE WHEN Amount = 10 THEN ... ELSE ... END
FROM
(
  SELECT bill.billnumber_id, billdetail.billclass, SUM(billdetail.amount) AS Amount
  GROUP BY bill.billnumber_id, billdetail.billclass
) A

或者只是重复聚合：

SELECT bill.billnumber_id, billdetail.billclass, SUM(billdetail.amount) AS Amount
     , CASE WHEN SUM(billdetail.amount) = 10 THEN ... ELSE ... END
GROUP BY bill.billnumber_id, billdetail.billclass

Answer 4

SELECT bill.billnumber_id, billdetail.billclass, (Select SUM(billdetail.amount) from billdetail)
AS Amount
from bill inner join billdetail on bill.id = buildetail.kBillId 
/* include from join (not added above)*/
GROUP BY bill.billnumber_id, billdetail.billclass

我相信这就是你所追求的......你可能希望在内部选择语句中包含相同的from结构：

 SELECT bill.billnumber_id, billdetail.billclass, (Select SUM(billdetail.amount) from bill inner
join billdetail on bill.id = buildetail.kBillId ) AS Amount
from bill inner join billdetail on bill.id = buildetail.kBillId 
/* include from join (not added above)*/
GROUP BY bill.billnumber_id, billdetail.billclass

如果这就是你的意思，请告诉我。

基于SUM的CASE语句导致查询

4 个答案: