Excel VBA: What is the best way to sum a column in a dataset with variable amounts of lines? - excel

Question

I need to sum two columns (B and C) in a dataset. The number of rows with data will vary between 1 and 17. I need to add the sums two rows beneath the last row of data (end result example in image 1).
My code worked beautifully for one dataset, but I am getting an error
Run-time error'6': Overflow
for a different dataset. What am I doing wrong?
'Units total
Windows("Final_Files.xlsb").Activate
Sheets("Revenue Summary").Select
lastrow = Worksheets("Revenue Summary").Cells(Rows.Count, 2).End(xlUp).Row
Dim a As Integer
a = 10000
For i = lastrow To 2 Step by - 1
a = a + Worksheets("Revenue Summary").Cells(i, 2).Value
Next
Worksheets("Revenue Summary").Cells(lastrow + 2, 2).Value = a
Correct End Result

Answer 1

You can try below sub-
Sub SumBC()
Dim sh As Worksheet
Dim lRowB As Long, lRowC As Long
Dim bSum As Double, cSum As Double
Windows("Final_Files.xlsb").Activate
Set sh = Worksheets("Revenue Summary")
lRowB = sh.Cells(sh.Rows.Count, 2).End(xlUp).Row
lRowC = sh.Cells(sh.Rows.Count, 3).End(xlUp).Row
bSum = WorksheetFunction.Sum(sh.Range("B2:B" & lRowB))
cSum = WorksheetFunction.Sum(sh.Range("C2:C" & lRowC))
sh.Cells(lRowB + 2, 2) = bSum
sh.Cells(lRowC + 2, 3) = cSum
sh.Activate
Set sh = Nothing
End Sub
Remember: If you want to run same sub multiple time then you need clear totals otherwise it will add totals again again below of last totals.

Answer 2

Your code is perfect but there is only one error. You have initialized variable 'a' with 10000. Change it to 0.
a = 0
then your code will be perfect.

Answer 3

Add Totals to Multiple Columns
If you're not OP: It is easy to test the code. Open a new workbook and insert a module. Copy the code into the module. Uncomment the Sheet1 line, and outcomment the Revenue Summary line. In worksheet Sheet1 add some numbers in columns 2 and 3 and your ready.
Run only the insertTotals procedure. The calculateSumOfRange is called when needed.
Play with the constants in insertTotals and change the values in the columns. Add text, error values, booleans to see how the code doesn't break.
The issue with Application.Sum or WorksheetFunction.Sum is that it fails when there are error values in the range. That's what the calculateSumOfRange is preventing. If there is an error value, the loop approach is used. If not, then Application.Sum is the result.
You can use the calculateSumOfRange in Excel as a UDF. Just don't include the cell where the formula is and you're OK, e.g. =calculateSumOfRange(A1:B10).
The Code
Option Explicit
Sub insertTotals()
Const FirstRow As Long = 2 ' First Row of Data
Const LastRowCol As Long = 2 ' The column where the Last Row is calculated.
Const TotalsOffset As Long = 2 ' 2 means: 'data - one empty row - totals'
Dim Cols As Variant
Cols = Array(2, 3) ' add more
'With ThisWorkbook.Worksheets("Sheet1")
With Workbooks("Final_Files.xlsb").Worksheets("Revenue Summary")
' Define Last Row ('LastRow') in Last Row Column ('LastRowCol').
Dim LastRow As Long
LastRow = .Cells(.Rows.Count, LastRowCol).End(xlUp).Row
' Define Last Row Column Range ('rng').
Dim rng As Range
Set rng = .Range(.Cells(FirstRow, LastRowCol), _
.Cells(LastRow, LastRowCol))
Dim j As Long
' Validate Columns Array ('Cols').
If LBound(Cols) <= UBound(Cols) Then
' Iterate columns in Columns Array.
For j = LBound(Cols) To UBound(Cols)
' Use 'Offset' to define the current Column Range and write
' its calculated total below it.
.Cells(LastRow + TotalsOffset, Cols(j)).Value = _
calculateSumOfRange(rng.Offset(, Cols(j) - LastRowCol))
Next j
End If
End With
End Sub
Function calculateSumOfRange(SourceRange As Range) _
As Double
' Initialize error handling.
Const ProcName As String = "calculateSumOfRange"
On Error GoTo clearError ' Turn on error trapping.
' Validate Source Range.
If SourceRange Is Nothing Then
GoTo NoRange
End If
' Calculate Sum of Range.
Dim CurrentValue As Variant
CurrentValue = Application.Sum(SourceRange)
Dim Result As Double
If Not IsError(CurrentValue) Then
Result = CurrentValue
Else
Dim Data As Variant
If SourceRange.Rows.Count > 1 Or SourceRange.Columns.Count > 1 Then
Data = SourceRange.Value
Else
ReDim Data(1, 1)
Data(1, 1) = SourceRange.Value
End If
Dim i As Long
Dim j As Long
For i = 1 To UBound(Data, 1)
For j = 1 To UBound(Data, 2)
CurrentValue = Data(i, j)
If IsNumeric(CurrentValue) And _
Not VarType(CurrentValue) = vbBoolean Then
Result = Result + CurrentValue
End If
Next j
Next i
End If
' Write result and exit.
calculateSumOfRange = Result
GoTo ProcExit
' Labels
NoRange:
Debug.Print "'" & ProcName & "': No range (Nothing)."
GoTo ProcExit
clearError:
Debug.Print "'" & ProcName & "': " & vbLf _
& " " & "Run-time error '" & Err.Number & "':" & vbLf _
& " " & Err.Description
On Error GoTo 0 ' Turn off error trapping.
GoTo ProcExit
ProcExit:
End Function

Answer 4

The following code summs up all the rows under "B2" and "C2". Adapt it to your needs.
' Keep a reference to the worksheet
Dim ws as Worksheet
Set ws = Worksheets("Revenue Summary")
' This is how many rows there are.
Dim rowCount as Long
rowCount = ws.Cells(ws.Rows.Count, 2).End(xlUp).Row-1
' This is the summation operation over each column
Dim b as Double, c as Double
b = WorksheerFunction.Sum(ws.Range("B2").Resize(rowCount,1))
c = WorksheerFunction.Sum(ws.Range("C2").Resize(rowCount,1))
' This writes the sum two cells under the last row.
ws.Range("B2").Cells(rowCount+2,1).Value = b
ws.Range("C2").Cells(rowCount+2,1).Value = c