VBA-条件求和B列，直到A列中的值更改

Question

Basic explanation. I am collecting all my multiple invoice data in one spreadsheet. Lets say I have only two columns that seperate each of the different invoice:

Serial ID.    Value

ABC001        $5.00
ABC001        $5.00
ABC001        $5.00
CBA100        $6.00
CBA100        $4.00
CBA100        $5.00

I want a VBA solution that would loop through columns, sum values in columnB UNTIL there is a change in columnA and THEN would put that sum value on columnC LAST ROW BEFORE THE CHANGE in columnA. The outpoot would look like this:

Serial ID.    Value   Total

ABC001        $5.00   
ABC001        $5.00
ABC001        $5.00   $15.00
CBA100        $6.00
CBA100        $4.00
CBA100        $5.00   $15.00

So far the closest thing I found was the solution by D Mason

But the problem with his code that the sum of the values in columnB adress is in EXACT row number WHERE THE CHANGE HAPPENS (not BEFORE), and it would run like this:

Serial ID.    Value   Total

ABC001        $5.00   $15.00   
ABC001        $5.00
ABC001        $5.00
CBA100        $6.00   $15.00
CBA100        $4.00
CBA100        $5.00

I am sure, that I made my problem clear. But just in case, the Serial Id will always stay in the same column, so will values. No sort will be performed. Sum if of whole range also is not good for me, becouse there may be duplicate invoices, and if function would take range (A:A) to lookup a conditional serial number, it would produce a false result. Thank you in advance, if there is some ways I could improve my question (if I get a correct answer and want it to be easier to find for others with the same problem), write a suggestion.

Answer 1

Please give this a try...

Sub GetTotal()
Dim rng As Range, cell As Range
Dim lr As Long
Dim Total As Double

Application.ScreenUpdating = False
lr = Cells(Rows.Count, 1).End(xlUp).Row
Set rng = Range("A2:A" & lr)
For Each cell In rng
    If cell = cell.Offset(1) Then
        Total = Total + cell.Offset(0, 1)
    Else
        Total = Total + cell.Offset(0, 1)
        cell.Offset(0, 2) = Total
        Total = 0
    End If
Next cell
Columns("C").NumberFormat = "$#,##0.00"
Application.ScreenUpdating = True
End Sub

Answer 2

Can you try following formula.

=IF(A2<>A1,SUMIF(A:A,A2,B:B),"")

Put the formula C2 cell as shown in screenshot.