If you want to get common user ID’s You can try below Query
ListA=(From p In dt1.Select()
where (From q in dt2.Select() where p(“User ID”).ToString.Equals(q(“User ID”).ToString) Select q).ToArray.Count>0
Select p(“User ID”).ToString ).ToList
You will get the List of common user ID’s .
dt1-First excel sheet
dt2-Second excel sheet
Regards,
Mahesh