Question

如何在SQL Server中为此编写逻辑：

Voucher #   Name   Amount 
-------------------------
 123        ABC     910
 123        ABC    -910
 224        XYZ     600

预期输出

Voucher #    Name     Amount   - (Amount)
-------------------------------------------
 123         ABC       910       -910
 224         XYZ       600         -

Answer 1

在这里使用条件聚合真的很简单。无需一遍又一遍地查询同一张表。

select Voucher
    , Name
    , Amount = sum(case when Amount > 0 then Amount else 0 end)
    , [-Amount] = sum(case when Amount < 0 then Amount else 0 end)
from YourTable
group by Voucher
    , Name

Answer 2

这是代码，尝试一下按负数和正数分组并进行左连接

DECLARE @tbl TABLE
(
    Voucher varchar(10),
    Name    varchar(100),
    Amount  int 
)

INSERT INTO @tbl
(
    Voucher,
    Name,
    Amount
)
VALUES
(123,'ABC',910),
(123,'ABC',-910),
(224,'XYZ',600)

SELECT t1.Voucher, t1.Name, t1.Amount , ISNULL(t2.Amount,0) AS [(-Amount)] FROM (
SELECT t.Voucher, Name, Sum(t.Amount) Amount 
FROM @tbl t
WHERE t.Amount > 0
GROUP BY t.Voucher, t.Name) t1 Left JOIN 
(SELECT t.Voucher, Name, Sum(t.Amount) Amount 
FROM @tbl t
WHERE t.Amount < 0
GROUP BY t.Voucher, t.Name) t2 ON t1.Voucher = t2.Voucher

Answer 3

如果每个(Voucher, Name)仅存在1个正数Amount和0个或1个负数Amount，则使用自连接：

select t.*, tt.amount NegativeAmount
from tablename t left join tablename tt 
on tt.voucher = t.voucher and tt.name = t.name and tt.amount < 0
where t.amount > 0

请参见demo。
结果：

> voucher | name | amount | NegativeAmount
> ------: | :--- | -----: | -------------:
>     123 | ABC  |    910 |           -910
>     224 | XYZ  |    600 |

为现有行中的-ve值创建新列

3 个答案: