如果没有行,如何让SQL Server返回默认值0？

Question

如果总和不返回任何行,如何获得默认值0？

编辑:我已编辑此帖子以添加更详尽的示例(前一个没有遇到过)

例如

 DECLARE @Item TABLE
(
    Id int,
    Price decimal,
    PricePer decimal
)

DECLARE @OrderItem TABLE
(
    Id int,
    ItemId int,
    ChargedPrice nvarchar(10),
    QtyRequired int,
    QtyLeftToDespatch int
)

INSERT INTO @Item (Id,Price,PricePer) VALUES (1,1.00, 1)
INSERT INTO @Item (Id,Price,PricePer) VALUES (2,2.00, 1)
INSERT INTO @Item (Id,Price,PricePer) VALUES (3,3.00, 1)
INSERT INTO @Item (Id,Price,PricePer) VALUES (4,4.00, 1)

INSERT INTO @OrderItem (Id, ItemId,ChargedPrice,QtyRequired,QtyLeftToDespatch) VALUES ( 1,1,100,100,50 )
INSERT INTO @OrderItem (Id, ItemId,ChargedPrice,QtyRequired,QtyLeftToDespatch) VALUES ( 2,1,200,300,50)
INSERT INTO @OrderItem (Id, ItemId,ChargedPrice,QtyRequired,QtyLeftToDespatch) VALUES ( 3,1,300,300,50 )

DECLARE @ItemIdTest int 
SET @ItemIdTest = 4

SELECT SUM((price/priceper)*QtyRequired) as total_value,
       SUM((price/priceper)*QtyRequired) as outstanding_value
FROM @Item i
INNER JOIN @OrderItem o ON i.Id = o.ItemId
WHERE i.Id = @ItemIdTest
group by itemId

这将返回

total_value, outstanding_value
==============
<No rows>

但我希望它返回0作为默认值.但是,如果您执行SELECT以选择它,那么将返回第二个SELECT以选择默认值,将返回2个结果集.

我可以一个人做吗？我看过COALESCE,但这只有在返回NULL时才有效,但事实并非如此.

编辑:我认为问题是与该组有关,但是有没有理由仍然没有任何结果回来？

Answer 1

试试这个

SELECT ISNULL(SUM(Debt) ,0)
FROM SupplierDebt
WHERE Id = @TestId

Answer 2

或者使用

SELECT COALESCE(SUM(Debt) ,0)
FROM SupplierDebt
WHERE Id = @TestId

COALESCE是ANSI标准,如果困扰您并且可以采用多个参数.

Answer 3

 DECLARE @Item TABLE
(
    Id int,
    Price decimal,
    PricePer decimal
)

DECLARE @OrderItem TABLE
(
    Id int,
    ItemId int,
    ChargedPrice nvarchar(10),
    QtyRequired int,
    QtyLeftToDespatch int
)

INSERT INTO @Item (Id,Price,PricePer) VALUES (1,1.00, 1)
INSERT INTO @Item (Id,Price,PricePer) VALUES (2,2.00, 1)
INSERT INTO @Item (Id,Price,PricePer) VALUES (3,3.00, 1)
INSERT INTO @Item (Id,Price,PricePer) VALUES (4,4.00, 1)

INSERT INTO @OrderItem (Id, ItemId,ChargedPrice,QtyRequired,QtyLeftToDespatch) VALUES ( 1,1,100,100,50 )
INSERT INTO @OrderItem (Id, ItemId,ChargedPrice,QtyRequired,QtyLeftToDespatch) VALUES ( 2,1,200,300,50)
INSERT INTO @OrderItem (Id, ItemId,ChargedPrice,QtyRequired,QtyLeftToDespatch) VALUES ( 3,1,300,300,50 )

DECLARE @ItemIdTest int 
SET @ItemIdTest = 4

SELECT COALESCE(SUM((price/priceper)*QtyRequired),0) as total_value,
       COALESCE(SUM((price/priceper)*QtyRequired),0) as outstanding_value
FROM @Item i
LEFT OUTER JOIN @OrderItem o ON i.Id = o.ItemId
WHERE i.Id = @ItemIdTest
group by itemId