SharePoint list Calendar double booking

[matt-beyond]

Hi All,

I have a sharepoint list acting as a calendar for booking 3 different rooms.

Columns: Room name, in date, out date

I wish to provide an error or notice or prevention if the user attempts to book a room that is already booked

Thanks

[#2]

Hi!
It's better if you build a PowerApps to handling and booking the room. Reason for this is that you can't block double booking in a calender i SharePoint
There is a template you can use:
https://powerapps.microsoft.com/en-us/blog/office-template-book-a-room-now-available/