SQL - SUM TotalValue returning a null with LEFT JOIN Clause - sql

Question

I'd to like SUM a TotalValue column based on Vendor and logged in user. I completely returning a right value of other info in logged user and the connected vendor, the problem is the SUM of TotalValue column is returning a null value. am I missing something?
This is what I've already tried:
SELECT ,v.VendorName ,
u.Product ,
v.[Description] ,
v.Status ,
SUM(cpm.TotalValue) AS TotalValue
FROM Vendor v
LEFT JOIN [ProductContract] c ON v.VendorId = c.VendorId
AND c.[Status] = 4
AND c.ProductContractId IN
(SELECT con.ProductContractId
FROM [ProductContract] con
INNER JOIN [ProductContractPermission] cp ON cp.ProductContractId = con.ProductContractId
WHERE cp.UserInfoId = #UserInfoId)
LEFT JOIN ProductContractPaymentMenu cpm ON c.ProductContractId = cpm.ProductContractId
AND c.[Status] = 4
AND c.VendorId = #VendorId
LEFT JOIN VendorContact vc ON v.VendorId = vc.VendorId
AND vc.[Type] = 1
LEFT JOIN UserInfo u ON vc.UserInfoId = u.UserInfoId
WHERE v.VendorId IN
(SELECT VendorId
FROM ClientVendor
WHERE ClientId = #VendorId)
GROUP BY v.VendorName,
u.Product,
v.[Description],
v.Status,
cpm.TotalValue
ORDER BY v.[Status],
v.CreatedOn

Answer 1

Seems that you want to apply an aggregate filter, this is the famous HAVING clause:
...
GROUP BY v.VendorName,
u.Product,
v.[Description],
v.Status,
cpm.TotalValue
HAVING
SUM(cpm.TotalValue) > 0
ORDER BY v.[Status],
v.CreatedOn

Answer 2

Hi i think you have to add ISNULL(value,defaultvalue) because cpm table was on left join and it can be null.
SELECT v.VendorName ,
u.Product ,
v.[Description] ,
v.Status ,
SUM(ISNULL(cpm.TotalValue,0)) AS TotalValue
FROM Vendor v
LEFT JOIN [ProductContract] c ON v.VendorId = c.VendorId
AND c.[Status] = 4
AND c.ProductContractId IN
(SELECT con.ProductContractId
FROM [ProductContract] con
INNER JOIN [ProductContractPermission] cp ON cp.ProductContractId = con.ProductContractId
WHERE cp.UserInfoId = #UserInfoId)
LEFT JOIN ProductContractPaymentMenu cpm ON c.ProductContractId = cpm.ProductContractId
AND c.[Status] = 4
AND c.VendorId = #VendorId
LEFT JOIN VendorContact vc ON v.VendorId = vc.VendorId
AND vc.[Type] = 1
LEFT JOIN UserInfo u ON vc.UserInfoId = u.UserInfoId
WHERE v.VendorId IN
(SELECT VendorId
FROM ClientVendor
WHERE ClientId = #VendorId)
GROUP BY v.VendorName,
u.Product,
v.[Description],
v.Status,
cpm.TotalValue
ORDER BY v.[Status],
v.CreatedOn
https://learn.microsoft.com/en-us/sql/t-sql/functions/isnull-transact-sql?view=sql-server-2017
Edit: other point you have miss ',' in your query after the SELECT.

Answer 3

Your left join on ProductContractPaymentMenu may not always get an item, so cpm.TotalValue can be NULL sometimes. When you use SUM and when one value is NULL then the result will be NULL. You might rewrite that part as:
SUM(ISNULL(cpm.TotalValue, 0)) AS TotalValue
In that case, it will treat non-existing records as value 0.