How can I compare cells in different rows and insert-right if lower cell if not the same? - excel

Question

How can I compare cells in two rows and and match the lower cell value to the upper cell value, if the two are different? Here is some the same data I am working with and what I hope to see after the code runs.
Before:
[ID_GLOBAL], [ID_UNIQUE], [ID_REAL], [ID_1], [ID_2], [GAS_ADJ], [OBJ_ADJ]
[ID_GLOBAL], [ID_UNIQUE], [ID_REAL], [GAS_ADJ], [OBJ_ADJ]
After:
[ID_GLOBAL], [ID_UNIQUE], [ID_REAL], [ID_1], [ID_2], [GAS_ADJ], [OBJ_ADJ]
[ID_GLOBAL], [ID_UNIQUE], [ID_REAL], NULL AS [ID_1], NULL AS [ID_2], [GAS_ADJ], [OBJ_ADJ]
I think the code will basically look like this, but I haven't gotten the insert-right working properly.
Sub CompareCellsDiffRows()
Dim bothrows As Range, i As Integer
Set bothrows = Selection
With bothrows
For i = 1 To .Columns.Count
If Not StrComp(.Cells(1, i), .Cells(2, i), vbBinaryCompare) = 0 Then
' magic happens here
End If
Next i
End With
End Sub
As you may have guessed, I'm dealing with hundreds of fields in several tables and trying to Union everything together, so all these field names have to match up in the correct order.
Thanks.

Answer 1

I am assuming, as per your example, that the first row is the one that will be always complete.
Sub CompareRowDifferences()
Dim sht As Worksheet
Dim i, LastColumn As Long
Set sht = ThisWorkbook.Worksheets("Transposed Fields")
LastColumn = sht.Cells.SpecialCells(xlLastCell).Column
With sht
For i = 1 To LastColumn
If StrComp(.Cells(1, i), .Cells(2, i), vbBinaryCompare) <> 0 Then
.Cells(2, i).Insert Shift:=xlToRight
.Cells(2, i).Value2 = "NULL AS " & .Cells(1, i).Value2
End If
Next i
End With
End Sub
Hope it helps
Regarding your second question (if they are not ordered) and assuming always that the first line is the ones that rules...
Sub CompareRowDifferences()
Dim sht As Worksheet
Dim i, j, LastColumn As Long
Set sht = ThisWorkbook.Worksheets("Transposed Fields")
LastColumn = sht.Cells.SpecialCells(xlLastCell).Column
j = 0
With sht
For i = 1 To LastColumn
Test = Application.WorksheetFunction.CountIf(Range _
(Cells(2, i), Cells(2, LastColumn + j)), .Cells(1, i).Value2)
If Test >= 1 Then
.Cells(2, i).Insert Shift:=xlToRight
.Cells(2, i).Value2 = .Cells(1, i).Value2
Else
.Cells(2, i).Insert Shift:=xlToRight
.Cells(2, i).Value2 = "NULL AS " & .Cells(1, i).Value2
End If
j = j + 1
Next i
Range(Cells(2, LastColumn), Cells(2, LastColumn + j)).ClearContents
End With
End Sub

Answer 2

This procedure identifies and uses the row with a higher number of fields (i.e. no-empty cells), and uses it as "model" to update the other row regardless of the position of the fields in the other row.
Sub Headers_Comparison(rInput As Range)
Dim aOut As Variant, aSrc As Variant, aTrg As Variant
Dim bMatch As Byte, bRow As Byte, b As Byte
With WorksheetFunction
Rem Validate Fields in Rows
If .CountA(rInput.Rows(1)) > .CountA(rInput.Rows(2)) Then
bRow = 2
aSrc = .Transpose(.Transpose(rInput.Rows(1).Value2))
aTrg = .Transpose(.Transpose(rInput.Rows(2).Value2))
Else
bRow = 1
aSrc = .Transpose(.Transpose(rInput.Rows(2).Value2))
aTrg = .Transpose(.Transpose(rInput.Rows(1).Value2))
End If
aOut = aTrg
For b = 1 To UBound(aSrc)
bMatch = 0
On Error Resume Next
bMatch = .Match(aSrc(b), aTrg, 0)
On Error GoTo 0
aOut(b) = IIf(bMatch > 0, vbNullString, "NULL AS ") & aSrc(b)
Next: End With
rInput.Rows(bRow).Value = aOut
End Sub
It should be called in this manner:
Call Headers_Comparison(rSel) 'update with required range

Answer 3

I think I just figured it out!
Sub CompareRowDifferences()
Dim i As Integer
Dim sht As Worksheet
Dim LastColumn As Long
Set sht = ThisWorkbook.Worksheets("Transposed Fields")
LastColumn = sht.UsedRange.Columns(sht.UsedRange.Columns.Count).Column
For i = 1 To LastColumn
If Not StrComp(sht.Cells(1, i), sht.Cells(2, i), vbBinaryCompare) = 0 Then
' magic happens here
Set Rng = sht.Cells(2, i)
Rng.Insert Shift:=xlToRight
sht.Cells(2, i).Value = "NULL AS " & sht.Cells(1, i).Value
End If
Next i
End Sub
This seems to work. Although, this is a pretty simple solution. I understand it would be much more complex if the order of names the lower row changed. This works ONLY because the names in row 2 match the names in row 1, there are just fewer names. I would love to see what the code would look like if the order of the row 2 names was switch around, compared to the row 1 names.