how to sum records with same id in query

[Attievv]

This is the result set on the query run below
---------------------------------------------------------------
TDP000499 RS 002259 PAYMENT - THANK YOU TDP000499 50.00
TDP000499 RS 002261 PAYMENT - THANK YOU TDP000499 80.00
TDP000499 RS 002262 PAYMENT - THANK YOU TDP000499 60.00
TDP000499 RS 002260 PAYMENT - THANK YOU TDP000499 220.00
TDP000500 RS 002260 PAYMENT - THANK YOU TDP000500 770.00
TDP000500 RS 002268 PAYMENT - THANK YOU TDP000500 80.00
TDP000501 RS 002268 44574 580.00
TDP000502 RS 002268 PAYMENT - THANK YOU TDP000502 190.00
TDP000502 RS 002270 PAYMENT - THANK YOU TDP000502 199.99

Column 1 = Payment serial
Column 2 = inv number paid(not important)
Column 3 = payment description
Column 4 = Amount paid

The purpose here is to group the data by column 1 (i.e. TDP00049 must give me one row with the total value of column 4 for the payment serial i.e. tdp000499 must sum = 410.00 ) Currently the bottom query gives me 50.00. It does not sum all 4 rows.

How can I change the query to get the correct result?

sTmp = "SELECT c.AccountNumber, " + vbCrLf
sTmp = sTmp + " c.CompanyName, " + vbCrLf
sTmp = sTmp + " ctx.TransactionDate, " + vbCrLf
sTmp = sTmp + " ctx.TransactionNumber, " + vbCrLf
sTmp = sTmp + " cs.OrderNumber, " + vbCrLf
sTmp = sTmp + " ctx.ReferenceNumber, " + vbCrLf

Select Case CustTypeID
Case Is = 1
sTmp = sTmp + " IF(LEFT(ctx.TransactionNumber,3) = 'TDP', IFNULL(ctx.PaymentDescription,ctx.TransactionDescription),
ctx.TransactionDescription) AS TransactionDescription, " + vbCrLf
Case Is = 2
sTmp = sTmp + " IF(LEFT(ctx.TransactionNumber,3) = 'IDP', IFNULL(ctx.PaymentDescription,ctx.TransactionDescription),
ctx.TransactionDescription) AS TransactionDescription, " + vbCrLf
End Select

sTmp = sTmp + " ctx.DebitAmount), ctx.CreditAmount " + vbCrLf
sTmp = sTmp + "FROM cust_trans ctx LEFT JOIN cust c ON (c.CustomerID = ctx.CustomerID) " + vbCrLf
sTmp = sTmp + " LEFT JOIN cust_sales cs ON (cs.TransactionNumber = ctx.TransactionNumber) " + vbCrLf
sTmp = sTmp + "WHERE ctx.TransactionDate BETWEEN '" & Format(Date1, "yyyy-MM-dd") & "' AND '" & Format(Date2, "yyyy-MM-dd") & "' AND " + vbCrLf
sTmp = sTmp + " c.AccountNumber BETWEEN '" & FormatSQL(String1) & "' AND '" & FormatSQL(String2) & "' AND " + vbCrLf
sTmp = sTmp + " c.CustTypeID = '" & CustTypeID & "' And " + vbCrLf
sTmp = sTmp + " ctx.TransactionDescription NOT LIKE '%Period Balancing%' " + vbCrLf
sTmp = sTmp + "GROUP BY ctx.TransactionNumber " + vbCrLf
sTmp = sTmp + "ORDER BY TransactionDate ASC, ctx.TransactionID ASC, TransactionNumber ASC, AccountNumber ASC;" + vbCrLf