ios - 使用 NSPredicate 查询 CloudKit 的 Date 为空(或 null 或其他)

Question

我想在 CloudKit 中查询所有具有空白日期 (0/00/0000 00:00:00) 的记录，但我不知道如何创建一个谓词来执行此操作。

这是我尝试过的方法以及相关的错误:

    let predicate = NSPredicate(format: "ready == nil")                     // <ready != nil>: <nil> is not a function expression
    let predicate = NSPredicate(format: "ready == NIL")                     // <ready == nil>: <nil> is not a function expression
    let predicate = NSPredicate(format: "ready != NULL")                        // <ready != nil>: <nil> is not a function expression
    let predicate = NSPredicate(format: "ready == %@", NSNull())            // NSNull not allowed in comparison expression
    let predicate = NSPredicate(format: "ready == $NULL")                   // Unable to parse the format string "ready == $NULL"
    let predicate = NSPredicate(format: "ready == $BLANK")                  // <ready == $BLANK>: <$BLANK> is not a function expression
    let blankDate: Date = Date.init()
    let predicate = NSPredicate(format: "ready == %@", blankDate as NSDate)

    let haveADate = NSPredicate(format: "ready > %@", NSDate.distantPast as NSDate)
    let predicate = NSCompoundPredicate(notPredicateWithSubpredicate: haveADate)    // Inverting a valid one doesn't work either

Answer 1

我相信您的问题类似于 this one .

而不是 "ready == %@" ，您应该尝试使用 "(ready >= %@) AND (ready <= %@)"有两个引用值可供比较。