VB.net Trying to find balance owed by customers

Hi
I am trying to use the following statement to combine the total in two tables (Invoices and Payments) so that I can find the balance owed by customer. I am not sure what I have done wrong. I hope the problem is fairly obvious

            oSQL = "select"
            oSQL = oSQL & " CustomerID, sum(amount) Amount, School, [Last Name], [First Name], [Contact No], [Child1], [Child2], [Child3]"
            oSQL = oSQL & " from"
            oSQL = oSQL & "("
            oSQL = oSQL & "select [Link ID] CustomerID, Amount * -1 As Amount, School, [Last Name], [First Name], [Contact No], [Child1], [Child2], [Child3] from payments Inner Join Customers On [LINK ID] = [CustID]"
            oSQL = oSQL & " union all "
            oSQL = oSQL & "select invoices.customerId, [inv amt] As Amount, School, [Last Name], [First Name], [Contact No], [Child1], [Child2], [Child3] from invoices Inner Join Customers On invoices.[CustomerID] = Customers.[CustID]"
            oSQL = oSQL & ") SubQuery"
            oSQL = oSQL & " where Amount > 0"
            oSQL = oSQL & " group by CustomerID, School, [Last Name], [First Name], [Contact No], [Child1], [Child2], [Child3]"
Murray BrownMicrosoft Cloud Azure/Excel Solution DeveloperAsked:
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Lee SavidgeCommented:
What problem are you getting? Any errors?
0
Murray BrownMicrosoft Cloud Azure/Excel Solution DeveloperAuthor Commented:
If I run the following statement I get 1375 invoiced for CustomerID 1

select invoices.customerId, Sum([inv amt]) As Amount, School, [Last Name], [First Name], [Contact No], [Child1], [Child2], [Child3] from invoices Inner Join Customers On invoices.[CustomerID] = Customers.[CustID]
group by CustomerID, School, [Last Name], [First Name], [Contact No], [Child1], [Child2], [Child3]

If I run the following statement I get -1800 paid for Customer ID 1

select [Link ID], Sum(Amount) * -1 As Amount, School, [Last Name], [First Name], [Contact No], [Child1], [Child2], [Child3] from payments Left Join Customers On [LINK ID] = [CustID]
group by [Link ID], School, [Last Name], [First Name], [Contact No], [Child1], [Child2], [Child3]

Now using the full statement mentioned in my question I a trying to get -425 as a result but I get 1375 which is the total Invoiced and not the difference
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Murray BrownMicrosoft Cloud Azure/Excel Solution DeveloperAuthor Commented:
I see where I may have gone wrong. I get the balance of -425 when I take the following line out
    oSQL = oSQL & " where Amount > 0"
This line was intended to only show a client balance that is positive but it has disrupted things
I hope I am making sense
0
Akilandeshwari NCommented:
Your table has negative values which are excluded when you are filtering by Amount > 0.
0

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Murray BrownMicrosoft Cloud Azure/Excel Solution DeveloperAuthor Commented:
thanks for the help
0
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