带有子查询的 NSPredicate

NSPredicate with SubQuery(带有子查询的 NSPredicate)

问题描述

我有这种关系:

player <—>> games <<—> quiz

并且想要获得所有测验而不是玩家的游戏，例如

and want to get all quiz not in a game of a player, like

SELECT * 
FROM ZQUIZ 
WHERE Z_PK NOT IN (SELECT ZQUIZ 
                   FROM ZGAME 
                   WHERE ZPLAYER == 1)

有人可以帮忙吗?

推荐答案

这可以通过 SUBQUERY 子句来完成.如果 myPlayer 是有问题的播放器:

This can be done with a SUBQUERY clause. If myPlayer is the player in question:

let predicate = NSPredicate(format:"SUBQUERY(games,$g, $g.player == %@).@count == 0", myPlayer)

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