VBA or formula to mark or delete rows if not in range

[thomassharp]

Hello,
On Excel 2010.
Not sure if VBA is necessary here: I have two work sheets. Sheet1 with 10000 rows and the Sheet2 with 500 or so. All of Sheet2's data is in Sheet1. Sheet2 is just one column with values in column A; if those values are not in a specified column on Sheet1, i.e. any extra values, what would be the best way to delete the rows or just mark mark them in a helper column for deletion? I can't highlight duplicates then work backwards to get unique values as there are hundreds of duplicates in the sheet already. Everything I have read so far is for the reverse i.e. deleting rows if values are contained in a range.

Thank you

 

[JoeMo]

Hello,
On Excel 2010.
Not sure if VBA is necessary here: I have two work sheets. Sheet1 with 10000 rows and the Sheet2 with 500 or so. All of Sheet2's data is in Sheet1. Sheet2 is just one column with values in column A; if those values are not in a specified column on Sheet1, i.e. any extra values, what would be the best way to delete the rows or just mark mark them in a helper column for deletion? I can't highlight duplicates then work backwards to get unique values as there are hundreds of duplicates in the sheet already. Everything I have read so far is for the reverse i.e. deleting rows if values are contained in a range.

Thank you

Assuming data in sheet1 are in A2:A10001 and data in Sheet2 are in A2:A501, in sheet2 cell B2 place this formula and copy down:
=IF(ISNA(MATCH(A2,Sheet1!$A$2:$A$10001,0)),0,1)

Now sort sheet2 columns A:B by col B, ascending and delete all the rows, if any, with a 0 in col B.