Expression for Valid If dropdown constraint with conditional to show only rows without related items?
I have a table called Drywall and pullls data from two more tables (Property and Rooms) which are referenced to each other. In the drywall form, there is a column that pulls the Property ID from adding a new drywall row from the related drywalls inline from the property detail, and trying to only show Rooms for that property that already don’t have a related drywall row. Pretty much, only want each room to have only one related drywall row and any new drywall forms will not show in the room dropdown rooms that already have related drywall. Using valid if in the property ID to filter the room ID to rooms related to that property. Hope this all makes sense. I have been beating my head with different commands, variations, save and tests.
Thanks for any help