How can I get a default value of 0 if a sum does not return any rows?
Edit: I have edited this post to add a more thorough example (which the previous one didn't encounter)
E.g.
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
This will return
total_value, outstanding_value
==============
<No rows>
But I want it to have 0 as the default value returned. However, if you do a SELECT to select it, then a second SELECT to select a default, 2 result sets will be returned.
Can I do it just in one? I have looked at COALESCE, but this only works if NULL is returned, which it isn't.
Edit: I think the problem is to do with the group with, but is there a reason why still it doesn't come back with any results?