Data Validation: Prevent Duplicate Entries in Excel

Guys it's restriction = count result don't get confused with with negative sign

Btw this guy is a great help 😃
Thanks for your content

यह ट्रिक libre office calc में वर्क नही कर रही है।
Plz provide solution

Instead of playing background music.. If you explained it would be more clear

i want to restrict duplicate entry in column A in data validation which i have did =COUNTIF($A$2:A9999,A1)=1 but along with this i want to restrict charactor to Max 30 Charactor how to do ?

Thanks a lot

Tq

Thanks a lot of you sir

You are the best!:D

Thanks for helping the excel learners/users an easy way to learn with your simple and effective videos.