Vlookup across multiple sheets - vba

Question

The idea behind this is to use vba vlookup on column G:AI from sheet11-13 to sheet1. Header ends at row 3 across all worksheets.
I have written the codes as below. The code stops at the ws1.Cells(r, c).Value = Application.WorksheetFunction.VLookup(ws1.Cells(r, 1).Value, ws2.Range("A1:AI500"), colnum, False) showing subset out of range and sometimes even
Run-time error '1004': Unable to get the VLookup property of the WorksheetFunction class.
Please advice on the way forward.
I Would like to send out files for better clarification but can't seem to find the attach function. Thank you !
Sub green_update()
Dim wb As Workbook, ws1 As Worksheet, ws2 As Worksheet
Set wb = ThisWorkbook
Set ws1 = wb.Sheets("Sheet1")
Set ws2 = wb.Sheets("Sheet13")
Dim bil As String
Dim lastrow As Long
Dim for_col As Long, i As Long, r As Long, c As Long, colnum As Long
r = 4: c = 7: colnum = 7
'mysheets = "sheet11:sheet12:sheet13"
'i would like to allow vlookup to search through all sheet 11-13
For for_col = 1 To ws2.Cells("4", Columns.Count).End(xlToLeft).column
lastrow = ws2.Cells(Rows.Count, "A").End(xlUp).row
For i = 1 To lastrow - 3
ws1.Cells(r, c).Value = Application.WorksheetFunction.VLookup(ws1.Cells(r, 1).Value, ws2.Range("A1:AI500"), colnum, False)
r = r + 1
Next
r = 4
colnum = colnum + 1
c = c + 1
Next
End Sub

Answer 1

As you have totally changed what you were asking.. I am posting another answer to make it clear.
Still your request is not totally clear so that some inputs may refer to wrong destinations but you can change those ones easily.
If you don't understand any part feel free to ask it again.
Option Explicit
Sub green_update()
Application.ScreenUpdating = False
Dim zaman As Double
zaman = Timer
Dim wb As Workbook, ws1 As Worksheet, wsNames as Worksheet
Set wb = ThisWorkbook
Set ws1 = wb.Sheets("Sheet1")
Dim colNo As Long, OthARowNo As Long, sh1ARowNo As Long
Dim for_col As Long, i As Long, r As Long, c As Long, colnum As Long
r = 4: c = 7: colnum = 7
For Each wsNames In Sheets(Array("sheet11", "sheet12", "sheet13"))
colNo = wsNames.Cells("4", Columns.Count).End(xlToLeft).column
'Column numbers are 35 but you are working between G:AI which is 29 columns!
OthARowNo = wsNames.Cells(Rows.Count, "A").End(xlUp).row
sh1ARowNo = ws1.Cells(Rows.Count, "A").End(xlUp).row
For for_col = 7 To colNo 'colNo Is 35 Green columns start at 7th column, totally 29 loop, till 35th one.
For i = 1 To sh1ARowNo 'This should run until sh1's row number
ws1.Cells(r, c).Value = Application.VLookup(ws1.Cells(r, 1).Value, wsNames.Range("A1:AI" & OthARowNo), colnum, False)
If IsError(ws1.Cells(r, c).Value) Then
ws1.Cells(r, c).Value = ""
End If
r = r + 1
Next i
r = 4
colnum = colnum + 1
c = c + 1
Next for_col
colnum = 7
c = c + 6 'There are 6 columns between AI:AP and BR:BY
Next wsNames
Application.ScreenUpdating = True
MsgBox Format(Timer - zaman, "00.00") & "secs"
End Sub

Answer 2

I explained my answer within the code, but to summarize your problems:
1- You don't define your variables, especially worksheets. Never Assume your worksheet and always define and set references to Workbooks and Worksheets
2- You are limiting your For loops with the Row number of A column and Column number of 3rd row, but what if they are empty or not compatible with your lookup rounds? Then you may get error or wrong results. Define them carefully.
Option Explicit
Sub green_update()
Dim wb As Workbook, ws1 As Worksheet, ws2 As Worksheet
Set wb = ThisWorkbook
Set ws1 = wb.Sheets("Sheet1") 'Change this Sheet1 name with your current Worksheet name
Set ws2 = wb.Sheets("mysheets")
Dim bil As String 'I don't know where do you use that variable.
Dim lastrow As Long 'Prefer to work with Long instead of Integer
Dim for_col As Long, i As Long, r As Long, c As Long, colnum As Long
r = 4: c = 7: colnum = 7
For for_col = 1 To ws2.Cells("4", Columns.Count).End(xlToLeft).Column
'This is important! Here in this case are you sure you, _
'you would like to define how many times your For loop will run based on 3rd row?
lastrow = ws2.Cells(Rows.Count, "A").End(xlUp).Row
'This is also important! Are you sure you would like to run your For loop_
'based on the row number of A column? I think you should define it -3 _
'because you start your lookup from D4 (so first 3 one Is not necessary)
For i = 1 To lastrow - 3
ws1.Cells(r, c).Value = WorksheetFunction.VLookup(ws1.Cells(r, 4).Value, ws2.Range("A1:AI500"), colnum, False)
r = r + 1
Next
r = 4
colnum = colnum + 1
c = c + 1
Next
End Sub