[excel] Excel compare two columns and highlight duplicates

I have an excel file with 10,000 rows in column A some values are the same.

Example:

A1 - P7767

A2 - P3443

A3 - P7767

A4 - P8746

A5 - P9435

etc...

I then have another column with 100 rows which have some of the values found in column A,

B1 - P7767

B2 - P8746

etc...

I need to highlight all cells in column A where the value is found in any of the values in column B

So basically column B checks to see if it can find the same value anywhere in column A, if true highlight the cell leaving any cells white when the value is not found in column B

I hope I have explained this well, I have done some research and I believe I need to use conditional formatting to get this result but I am really stuck on the formula to use and cannot seem to find an example online (Maybe I am not searching the correct term as I'm not sure on what this is exactly called)

Don't wana do soo much work guyss.. Just Press Ctr and select Colum one and Press Ctr and select colum two. Then click conditional formatting -> Highlight Cell Rules -> Equel To.

and thats it. your done. :)

A1 --> conditional formatting --> cell value is B1 --> format: whatever you want

hope that helps

NOTE: You may want to remove duplicate items (eg duplicate entries in the same column) before doing these steps to prevent false positives.

1. Select both columns
2. click Conditional Formatting
3. click Highlight Cells Rules
4. click Duplicate Values (the defaults should be OK)
5. Duplicates are now highlighted in red:

Suppose you want to compare a column A and column H in a same spreadsheet .

You need to go another column next to these 2 columns and paste this formula : =(Sheet1!A:A=Sheet1!H:H) this will display FALSE or TRUE in the column . So you can use this new column to color the non matching values using conditional color formatting feature .

The easiest way to do it, at least for me, is:

Conditional format-> Add new rule->Set your own formula:

=ISNA(MATCH(A2;$B:$B;0))

Where A2 is the first element in column A to be compared and B is the column where A's element will be searched.

Once you have set the formula and picked the format, apply this rule to all elements in the column.

Hope this helps

I was trying to compare A-B columns and highlight equal text, but usinng the obove fomrulas some text did not match at all. So I used form (VBA macro to compare two columns and color highlight cell differences) codes and I modified few things to adapt it to my application and find any desired column (just by clicking it). In my case, I use large and different numbers of rows on each column. Hope this helps:

Sub ABTextCompare()

Dim Report As Worksheet
Dim i, j, colNum, vMatch As Integer
Dim lastRowA, lastRowB, lastRow, lastColumn As Integer
Dim ColumnUsage As String
Dim colA, colB, colC As String
Dim A, B, C As Variant

Set Report = Excel.ActiveSheet
vMatch = 1

'Select A and B Columns to compare
On Error Resume Next
 Set A = Application.InputBox(Prompt:="Select column to compare", Title:="Column A", Type:=8)
  If A Is Nothing Then Exit Sub
colA = Split(A(1).Address(1, 0), "$")(0)
 Set B = Application.InputBox(Prompt:="Select column being searched", Title:="Column B", Type:=8)
   If A Is Nothing Then Exit Sub
  colB = Split(B(1).Address(1, 0), "$")(0)
 'Select Column to show results
 Set C = Application.InputBox("Select column  to show results", "Results", Type:=8)
    If C Is Nothing Then Exit Sub
  colC = Split(C(1).Address(1, 0), "$")(0)

'Get Last Row
lastRowA = Report.Cells.Find("", Range(colA & 1), xlFormulas, xlByRows, xlPrevious).Row - 1 ' Last row in column A
lastRowB = Report.Cells.Find("", Range(colB & 1), xlFormulas, xlByRows, xlPrevious).Row - 1 ' Last row in column B

 Application.ScreenUpdating = False
'***************************************************
For i = 2 To lastRowA
      For j = 2 To lastRowB
          If Report.Cells(i, A.Column).Value <> "" Then
              If InStr(1, Report.Cells(j, B.Column).Value, Report.Cells(i, A.Column).Value, vbTextCompare) > 0 Then
                  vMatch = vMatch + 1
                  Report.Cells(i, A.Column).Interior.ColorIndex = 35 'Light green background
                  Range(colC & 1).Value = "Items Found"
                  Report.Cells(i, A.Column).Copy Destination:=Range(colC & vMatch)
                  Exit For
              Else
                  'Do Nothing
              End If
          End If
      Next j
  Next i
If vMatch = 1 Then
    MsgBox Prompt:="No Itmes Found", Buttons:=vbInformation
End If
'***************************************************
Application.ScreenUpdating = True

End Sub

A simple formula to use is

=COUNTIF($B:$B,A1)

Formula specified is for cell A1. Simply copy and paste special - format to the whole of column A