Is it possible use nested SUBQUERY in NSPredicate?

问题

As you can see I have two one-many relationships. Is it possible to write such a nested SUBQUERY where I want to select all A, where any of the belonging C-s under any of belonging B to A satisfy a certain condition?

回答1:

You can nest SUBQUERY in a predicate. But it seems that a single SUBQUERY is sufficient here (if ds is a to-one relationship from C to D), for example

[NSPredicate predicateWithFormat:@"SUBQUERY(bs, $x, ANY $x.cs.ds.name = %@).@count > 0", name];

来源：https://stackoverflow.com/questions/13224601/is-it-possible-use-nested-subquery-in-nspredicate