Swift coreData - format date and use it in predicate

Question

H. I have an entity called Agendadate and one called AgendaEvent. AgendaEvent has a many to many relation with AgendaDate (agendaDates).

in my AgendaDate i have an objec

Answer 1

Don't use a custom string format for that purpose. You want to fetch all entries which are related to an Agendadate object with a date on the same day as the given day.

So you compute the start and end of that day first:

let date = Date()

let cal = Calendar.current
let startOfDay = cal.startOfDay(for: date)
let endOfDay = cal.date(byAdding: .day, value: 1, to: startOfDay)!

Then use this SUBQUERY:

let predicate = NSPredicate(format: "SUBQUERY(agendaDates, $a, $a.dates >= %@ AND $a.dates < %@).@count > 0",
                            startOfDay as NSDate, endOfDay as NSDate)

It tests $a.dates >= startDate AND $a.dates < endDate for all related objects, and yields true if there is at least one matching the condition.