DataTable select rows where debit and credits match - wpf

Question

Where a DataTable has the following Columns
Account Number (Integer) (Unique)
Debit (Decimal)
Credit (Decimal)
Selected (Boolean)
There may be several rows with the same account number and either a Debit Entry or a Credit Entry. What I am attempting to do is match up the debits and credits where they add up to the same value and mark them as selected by iterating through all the rows. Any idea on the best method to achieve this?
Thanks
e.g.
SQL
strSQL = "SELECT A_Sales_Ledger.Transaction_ID as 'Transaction', "
strSQL += "Customers.Cust_No as 'Acct', "
strSQL += "Customers.Cust_Name as 'Name', "
strSQL += "Customers.Add1 as 'Unit', "
strSQL += "A_Sales_Ledger.Debit as 'Debit', "
strSQL += "A_Sales_Ledger.Credit as 'Credit', "
strSQL += "A_Sales_Ledger.Document_Date as 'Date', "
strSQL += "A_Sales_Ledger.S_Description as 'Description' "
strSQL += "FROM A_Sales_Ledger "
strSQL += "JOIN Customers ON Customers.Customer_ID = A_Sales_Ledger.Customer_ID "
strSQL += "WHERE A_Sales_Ledger.Paid = 'N' "
strSQL += "ORDER BY Customers.Cust_No"

Answer 1

This may not be the best solution but it does seem to work...
I'm making three passes though the DataTable
Pass one - if the total of the debits equals the total of the credits for each customer mark them as selected
Pass two - Add the total of the credits for the customer and iterate though the debits until the same value is achieved and mark them as selected
Pass three - mop up any remaining credit entries that match a debit entry for the same customer...
For Each Row As DataRow In BalanceDT.Rows
Dim vAcct As String = Row("Acct")
Dim vDebits As Decimal = BalanceDT.Compute("SUM(Debit)", "Acct = '" & vAcct & "'")
Dim vCredits As Decimal = BalanceDT.Compute("SUM(Credit)", "Acct = '" & vAcct & "'")
If vDebits = vCredits Then
Row("Selected") = True
End If
Next
Dim CurrentCust As String = ""
Dim TransactionDT As New DataTable
Dim ExitFor As Boolean = False
With TransactionDT.Columns
.Add("ID", GetType(Integer))
End With
For Each Row As DataRow In BalanceDT.Rows
Dim vAcct As String = Row("Acct")
ExitFor = False
TransactionDT.Rows.Clear()
If Not CurrentCust = vAcct Then
Dim vCredits As Decimal = BalanceDT.Compute("SUM(Credit)", "Acct = '" & vAcct & "'")
Dim vSelected() As DataRow = BalanceDT.Select("Acct = '" & vAcct & "'", Nothing)
For Each SubRow As DataRow In vSelected
If SubRow("Selected") = False Then
vCredits -= SubRow("Debit")
With TransactionDT.Rows
.Add(SubRow("Transaction"))
End With
If vCredits = 0 Then
ExitFor = True
Exit For
End If
End If
Next
If ExitFor = True Then
For Each SubRow As DataRow In vSelected
If SubRow("Credit") > 0 Then
SubRow("Selected") = True
End If
If SubRow("Debit") > 0 Then
For Each CustomerRow As DataRow In TransactionDT.Rows
If CustomerRow("ID") = SubRow("Transaction") Then
SubRow("Selected") = True
End If
Next
End If
Next
End If
End If
CurrentCust = vAcct
Next
For Each Row As DataRow In BalanceDT.Rows
Dim vAcct As String = Row("Acct")
If Not CurrentCust = vAcct Then
Dim vSelected() As DataRow = BalanceDT.Select("Acct = '" & vAcct & "' AND Selected = 'False'", "Credit")
For Each SubRow As DataRow In vSelected
If SubRow("Selected") = False Then
Dim vCredit As Decimal = SubRow("Credit")
For Each CustomerRow In vSelected
If CustomerRow("Selected") = False Then
Dim vDebit As Decimal = CustomerRow("Debit")
If Not vDebit = 0 And Not vCredit = 0 Then
If vDebit = vCredit Then
With TransactionDT.Rows
CustomerRow("Selected") = True
SubRow("Selected") = True
End With
Exit For
End If
End If
End If
Next
End If
Next
End If
CurrentCust = vAcct
Next