是否可以在NSPredicate中使用嵌套的SUBQUERY? [英] Is it possible use nested SUBQUERY in NSPredicate?

问题描述

如您所见，我有两个一对多的关系.是否可以在我要选择所有A的情况下编写这样的嵌套子查询，其中所有属于A的B下的所有C-s都满足特定条件?

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?

推荐答案

您可以将SUBQUERY嵌套在谓词中.但是，这里似乎只有一个子查询就足够了(例如，如果ds是从C到D的一对一关系)

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];

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