Greets, everybody! Please refer to the attached.

What I want to do is set a conditional formatting calc so that if there's an overlap of time for a reserved court (as shown in the attachment), the records within that overlap will turn red to signal the user that there's a time conflict. How do I pull this off? (I have yet to figure how to prevent that from happening in the first place, but I'm guessing I could re-engineer the needed calc so that when a new record is created, it will search for a time conflict before being recorded.)

I'm guessing that the answer involves converting the date and time into a concatenated string of numbers then using the MIN and MAX calcs to see if they fall within a range; I also suspect that a self-join table (or e-SQL?) will be needed as well, but I'm just stymied on how to move forward with this thing.

TIA for your help!

A self-join of your table would be convenient, say:

Reservations::Date = Reservations 2::Date
AND
Reservations::TimeIn ≤ Reservations 2::TimeOut
AND
Reservations::TimeOut ≥ Reservations 2::TimeIn
AND
Reservations::ReservationID ≠ Reservations 2::ReservationID

If there are any related records from Reservations 2, then there's a conflict.

Beauty! Thanks!