Formula to find unique rows

[Vntiger14]

Im trying to compare two worksheets in the same workbook that are 95% identical. sheet1 have columns A and B and contains 975000 rows and sheet2 have columns A and B and contains 1000000 rows. I need a formula to highlight/display the unique values in sheet2.

I'm using this formula
=IF(COUNTIFS(A3,sheet2!A:A,B3,sheet2!B:B)>0,"""",""UNIQUE"")

It work fine except when the rows from sheet1 does not match the rows from sheet2.

Any help is greatly appreciated. Thanks

 

[onlyadrafter]

Hello,

this may make the file large and slow (due to the number of rows)

On Sheet 2 cell C1, enter

=IF(ISERROR(MATCH(A1&B1,Sheet1!$A$1:$A$100000&Sheet1!$B$1:$B$100000,0)),"UNIQUE","")

you need to press CTLR + SHIFT + ENTER (array formula).
and copy down as far as required.

Is this what you expect? (Your post seems a bit contradictory regarding which sheet to check).