Delete ALL duplicate rows based on multiple columns

Question

The code below is currently deleting all duplicate occurances, including the original, found in column A. I would like to modify the code below to delete all duplicates based on columns A, B, C & D. To clarify, for rows 1 and 2 if columns A match, B match, c match and d match both rows would be deleted. Would anyone be able to assist? I believe an array is needed here, but unsure how. Thanks!

Dim toDel5(), p As Long
Dim RNG5 As Range, Cell5 As Long
Set RNG5 = Range("a1:a4000") 'set your range here

For Cell5 = 1 To RNG5.Cells.Count
    If Application.CountIf(RNG5, RNG5(Cell5)) > 1 Then
        ReDim Preserve toDel5(p)
        toDel5(p) = RNG5(Cell5).Address
        p = p + 1
    End If
Next

On Error GoTo NO_DUPLICATES
For p = UBound(toDel5) To LBound(toDel5) Step -1
    Range(toDel5(p)).EntireRow.Delete

Next p
On Error GoTo 0


End With 
NO_DUPLICATES:

if you are using xl2007+ then you can use RemoveDuplicates — Siddharth Rout
– Siddharth Rout, Commented Jun 17, 2013 at 14:58

score 1 · Accepted Answer · 2013-06-17 16:02:38Z

This problem seems to require a custom algorithm. Not sure if the aforementioned RemoveDuplicates can deliver a reliable answer for a not-so-simple case, but in this kind of situations I prefer to create something from scratch. As far as your code is not too flexible, I couldn't find the way to propose my correction and thus I have created the whole loop (what I shouldn't do). Note that this code can be adapted to any number of analysed columns/rows. Also bear in mind that it relies on an on-time deletion of the target cells (instead removing the whole row, what can only be done outside the loop); this is just to show you another alternative solution; you can change this code as much as you wish.

Dim maxRow As Long
Dim curStep, startColumn, endColumn As Integer
Dim areDuplicated As Boolean
curStep = 2 'No of rows to be considered
startColumn = 1
endColumn = 4
maxRow = 4000
For curRow = 1 To maxRow - 1
    areDuplicated = True
    For curColumn = startColumn To endColumn
        For curRow2 = curRow + 1 To curRow + curStep - 1
           If (IsEmpty(RNG5.Cells(curRow, curColumn)) Or RNG5.Cells(curRow, curColumn) <> RNG5.Cells(curRow2, curColumn)) Then
              areDuplicated = False
              Exit For
           End If

           If (Not areDuplicated) Then
              Exit For
           End If
        Next
    Next

    If (areDuplicated) Then
        For curRow3 = curRow To curRow + curStep - 1
            For curCol3 = startColumn To endColumn
                RNG5.Cells(curRow3, curCol3).Value = ""
            Next
        Next
    End If
Next

Zachary Smith · Accepted Answer · 2013-06-18 02:04:22Z

Thanks Varocarbas, that's a bit simplier than the code I ended up using. The code I used is below in case anyone wanted to see another option. Thanks for the help!

Dim r As Long, c As Long, n As Long, x As Long  
Dim rData As Range 

Application.ScreenUpdating = False 
n = ActiveSheet.Cells(1, 1).CurrentRegion.Columns.Count + 1 
ActiveSheet.Cells(1, n).Value = "TEMP" 

For r = 2 To ActiveSheet.Cells(1, 1).CurrentRegion.Rows.Count 
    ActiveSheet.Cells(r, n).Value = r 
Next r 

Set rData = ActiveSheet.Cells(1, 1).CurrentRegion 

With ActiveSheet.Sort 
    .SortFields.Clear 

    For c = 1 To n
        .SortFields.Add Key:=rData.Cells(1, c).Resize(rData.Rows.Count - 1, 1) 
    Next c 

    .SetRange rData 
    .Header = xlYes 
    .MatchCase = False 
    .Orientation = xlTopToBottom 
    .SortMethod = xlPinYin 
    .Apply 
End With 

With rData 
    For r = 2 To .Rows.Count 
         x = 0 
         For c = 1 To n
            If .Cells(r, c).Value <> .Cells(r + 1, c).Value Then 
                x = x + 1 
                Exit For 
            End If 
             Next c 
         If x = 0 Then 
            .Cells(r, n).Value = True 
            .Cells(r + 1, n).Value = True 
        End If     
    Next r 
End With 

With ActiveSheet.Sort 
    .SortFields.Clear 
    .SortFields.Add Key:=rData.Cells(1, n).Resize(rData.Rows.Count - 1, 1) 
    .SetRange rData 
    .Header = xlYes 
    .MatchCase = False 
    .Orientation = xlTopToBottom 
    .SortMethod = xlPinYin 
    .Apply 
End With 

On Error Resume Next 
rData.Columns(n).SpecialCells(xlCellTypeConstants, xlLogical).EntireRow.Delete 
On Error Goto 0 

rData.Columns(n).EntireColumn.Delete 
Application.ScreenUpdating = True

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