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.是否可以编写这样一个嵌套的子查询，我想选择所有 A，其中任何属于 A 的 B 下的任何属于 C 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

您可以在谓词中嵌套 SUBQUERY.但是这里似乎单个 SUBQUERY 就足够了(如果 ds 是从 C 到 Dto-one 关系>)，例如

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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