12 lists into one while removing duplicates, how?

I need to find a way to create a masterlist which is updated with only new unique entries every time I populate new lists (January - December).

I have attached an image showing what I want to do. The ID:s in the image are unique and will never have two names assigned to it.

As for name and salary columns I can link those myself, they are currently there only to illustrate the purpose.


Now to what I actually need help with:

Should I enter ID:s 1, 5, 10-18 under April (and corresponding information for name, salary etc) I want the master list to ignore ID:s 1, 5, 10-12 and only add ID:s 13-18 to the master list. How?

Thanks for any help.

Hi Taxster

If you copy all the existing ID's, Names, Salaries into a Master list and then use DATA, Remove duplicates it will give you an initial Master listing. Each month you can copy the ID's and Names and paste to the bottom of the Master List and then use DATA, Remove duplicates to update the Master List.

Terry

Thanks for the welcome and the input.

Ramananhrm: Should you come up with a solution without helper columns, please share. I will try to experiment with getting the helper column to work for now.

tandwfund: Thanks for this tip. However, I am looking for a solution which will handle this automatically and thereby minimizing the risk for human error.