What is wrong in my nested SUBQUERY predicate?

问题:

I have the data model you can see below, and a nested SUBQUERY predicate, but in somehow it just not works. Any idea how to correct it?

I figured out, this here down is working finally:

[NSPredicate predicateWithFormat:@"SUBQUERY(bs, $B, SUBQUERY($B.cs, $C, $C.ds.name != \"xxx\").@count > 0).@count > 0"];

回答1:

Ok, so here is the working solution:

[NSPredicate predicateWithFormat:@"SUBQUERY(bs, $B, SUBQUERY($B.cs, $C, $C.ds.name != \"xxx\").@count > 0).@count > 0"];