compare column with unique identifier in vba excel - excel

Question

I need to compare the data with unique identifier which is the concatenation of (Column A, "~" Column B) and store it in Column F. Find all the duplicate values in ColumnF, which will used as a basis for comparing to the other Columns (Column C, Column D and Column E). For example,
In my example, I have a duplicate value of 5*2018~OPS$CABUCKLE, in this case I will compare each column using the identifier. In my 1st entry, Column C have the same value in 2nd entry which is 222, but in Column D the value of 1st entry is N and it was changed to Y in 2nd entry. Same case in Column E. I need to highlight the changes happened between the entries.
I only did the concatenation in VBA, but I don't know how will I find the duplicate value and compare the other column?
Sub split1()
Dim ws As Worksheet, lRow As Long
Dim x As Long
Set ws = ThisWorkbook.ActiveSheet
lRow = ws.Cells(Rows.Count, 1).End(xlUp).Row
With ws
For x = 1 To lRow
For Each wrd In .Cells(x, 1)
d = wrd
For Each nm In .Cells(x, 2)
.Cells(x, 6).Value = d & "*" & nm
Next nm
Next
Next x
End With
End Sub

Answer 1

This could achieve what you're looking for, let me know if it misses anything
Just don't forget to go to Tools > References and check 'Microsoft Scripting Runtime'
Sub highlight()
' need to include Microsoft Scripting Runtime in Tools > References
Dim prevIDs As Scripting.Dictionary: Set prevIDs = New Scripting.Dictionary
Dim ws As Worksheet: Set ws = ThisWorkbook.ActiveSheet
Dim lastRow As Long
Dim oldRow As Long
Dim row As Long
Dim id As String
With ws
lastRow = .Cells(.Rows.Count, 1).End(xlUp).row
For row = 2 To lastRow
' set lookup value
.Cells(row, "F").Value = Trim(CStr(.Cells(row, "A").Value)) & "~" & Trim(CStr(.Cells(row, "B").Value))
id = .Cells(row, "F").Value
If prevIDs.Exists(id) Then
' get previously found row
oldRow = prevIDs(id)
If .Cells(row, "C").Value = .Cells(oldRow, "C").Value Then
' only checks if col D doesn't match -- can change to check both
If .Cells(row, "D").Value <> .Cells(oldRow, "D").Value Then
.Range("D" & row & ":E" & row).Interior.Color = RGB(100, 200, 100)
.Range("D" & oldRow & ":E" & oldRow).Interior.Color = RGB(100, 200, 100)
End If
End If
' reset last found row
prevIDs(id) = row
Else
prevIDs.Add id, row
End If
Next
End With
End Sub
Here's my test: