I'm googling the answer, but I recalled there are a lot of excell wizards here, so figured I'd ask y'all too:
I'm setting up an excell book for work, as a scheduling tool. Each book is one month, and has a tab for each day. ("February" book has 29 tabs)
I have a column which my team members will be entering numerical data (PO numbers) into, and I would like to set up a data validation rule so that they can not enter a duplicate. I know I need to use the "COUNTIF=1" function, but how do I format the selection to look at all the tabs in the book?
Thanks for the help!