Excel VBA Sum from Multiple Sheets - excel

Question

I am trying to create a function or functions that can sum daily hours from time cards for each client to come up with the total hours worked per day. Each client has it's own sheet inside of a single workbook.
Currently, I have a function that determines the sheet that goes with the first client (the third sheet in the workbook):
Function FirstSheet()
Application.Volatile
FirstSheet = Sheets(3).Name
End Function
And one to find the last sheet:
Function LastSheet()
Application.Volatile
LastSheet = Sheets(Sheets.Count).Name
End Function
The part that I am having trouble with it getting these to work within the sum function.
=sum(FirstSheet():LastSheet()!A1
That is basically what I want to accomplish. I think the problem is that I don't know how to concatenate it without turning it into a string and it doesn't realize that it is sheet and cell references.
Any help would be greatly appreciated.

Answer 1

So, an example formula would look like this:
=SUM(Sheet2!A1:A5,Sheet3!A1:A5,Sheet4!A1:A5)
That would sum Sheet2-Sheet4, A1:A5 on all sheets.
Is there a reason you need to write the VBA code to do this?
Can't you just enter it as a formula once?
Also, if you're going to the trouble of writing VBA to generate a formula, it may make more sense to just do the sum entirely in VBA code.
If not, try this:
Sub GenerateTheFormula()
Dim x, Formula
Formula = "=SUM(" 'Formula begins with =SUM(
For x = 3 To Sheets.Count
Formula = Formula & Sheets(x).Name & "!A1," 'Add SheetName and Cell and Comma
Next x
Formula = Left(Formula, Len(Formula) - 1) & ")" 'Remove trailing comma and add parenthesis
Range("B1").Formula = Formula 'Where do you want to put this formula?
End Sub
Results:

Answer 2

The functions return strings and not actual worksheets. The Worksheet does not parse strings well. So add a third function that uses the Evaluate function:
Function MySum(rng As Range)
MySum = Application.Caller.Parent.Evaluate("SUM(" & FirstSheet & ":" & LastSheet & "!" & rng.Address & ")")
End Function
Then you would simply call it: MySum(A1)
It uses the other two function you already have created to create a string that can be evaluated as a formula.

Answer 3

I didn't understand ur question completely but As I understood u have different sheets of different clients which contains supoose column 1 date and column 2
contains hours on that particular date wise hours and a final sheet which column1 contains name of client and column 2 contains total hoursPlease try it
Sub countHours()
Dim last_Row As Integer
Dim sum As Double
sum = 0
'Because I know number of client
For i = 1 To 2 'i shows client particular sheet
last_Row = Range("A" & Rows.Count).End(xlUp).Row
Sheets(i).Activate
For j = 2 To last_Row
'In my Excel sheet column 1 contains dates and column 2 contains number of hours
sum = sum + Cells(j, 2)
'MsgBox sum
Next j
'Sheet 3 is my final sheet
ThisWorkbook.Sheets(3).Cells(i + 1, 2).Value = sum
sum = 0
Next i
End Sub
Happy Coding :