Google sheets help

Job ID: 33922320

Budget: ₹1,500 – ₹2,000 INR

Hi
I have a large google spreadsheet in which I have around 4 lakh rows with contact information like First Name, Last name. email etc... I want to have a code or a query when a person types the same contact in another google spreadsheet it should come as a duplicate contact scanning the other google sheet.

This is because the google sheet is large and hanging and many users are using the same google sheet it is slow and freeze in between. Any recommendation or solution is welcome.
Related categories: Python Excel R Programming Language Google Sheets