I have a list of 100,000 patients that were invited to a study. Of these, 3,000 signed up and 500 requested they not be contacted again. I have a new list of 60,000 patients , with some overlap from the first list. So before I invite patients from the new list, I need to remove those who previously consented and those who previously asked not to be contacted. As they are patients, they have unique identifiers associated with each name.
I can see how to remove duplicate line items, but not how to subtract/remove completely patients on one list from another when I have so many to subtract. If it was 10 or so patients, I can do that manually, but not 500 or 3000.
You could add a column to the second list using the MATCH function matching the ID of the current row to the ID column of the first list: =MATCH(A2,Sheet2!$A$2:$A$3001,0) Next filter the new column and UNCHECK the #N/A entry. THen delete all visible rows and unfilter the list.