set a new reservation start date outside the existing reservation dates

[MJvanEwijk]

Hi,

I have a reservation table with start and end date for a specific tool 

The next reservation for that specific tool can not be made within an existing start/end date range or overlapping the range. Only outside the range and later than TODAY() is possible.

How can I set a valid if or set this up.

Thanks Muk

[Joseph_Seddik]

Please check these recent community posts by @rainnic :

https://www.googlecloudcommunity.com/gc/AppSheet-Q-A/How-to-check-if-even-one-room-is-already-booked... 

https://www.googlecloudcommunity.com/gc/AppSheet-Q-A/How-to-create-a-relationship-between-a-list-of-...

[Marc_Dillon]

Also search for "prevent duplicates" in general.