Ios 核心数据异常错误-无效的获取请求：没有userInfo为（null）的GROUP BY

我收到一个运行时错误，它说：

无效的获取请求：没有userInfo为null的GROUP BY

在我的代码中写着//error的地方：

let request = NSFetchRequest<NSFetchRequestResult>(entityName: CoreDataStrings.entityAffirmation)
let predicate = NSPredicate(format:"recordName == %@", privateRecord.recordID.recordName)
request.havingPredicate = predicate

print("predicte =", predicate)

do {
    let affirmationEntityInstances: [Affirmation] = try managedObjectContext.fetch(request) as! [Affirmation] // error here
    print("result =", affirmationEntityInstances)
    ...
} catch {
    ...
}

代码永远不会到达带有注释//错误的行之后的print语句。该错误不是catch语句捕获的错误

下面是调试窗口的结果，从print语句开始打印谓词

predicte = recordName == "F9DB2EE8-B693-44B7-BA2B-3EAB689A9940"
2019-07-17 14:05:50.409279-0500 Affirmations[68672:14476409] [error] error: SQLCore dispatchRequest: exception handling request: <NSSQLFetchRequestContext: 0x6000019402a0> , Invalid fetch request: HAVING with no GROUP BY with userInfo of (null)
CoreData: error: SQLCore dispatchRequest: exception handling request: <NSSQLFetchRequestContext: 0x6000019402a0> , Invalid fetch request: HAVING with no GROUP BY with userInfo of (null)
2019-07-17 14:05:50.625355-0500 Affirmations[68672:14476409] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Invalid fetch request: HAVING with no GROUP BY'
*** First throw call stack:
(
    0   CoreFoundation                      0x000000010fb596fb __exceptionPreprocess + 331
    1   libobjc.A.dylib                     0x000000010eb7cac5 objc_exception_throw + 48
    2   CoreData                            0x000000010f61aeb0 -[NSSQLGenerator newSQLStatementForRequest:ignoreInheritance:countOnly:nestingLevel:nestIsWhereScoped:requestContext:] + 1584
    3   CoreData                            0x000000010f62549e -[NSSQLiteAdapter _statementForFetchRequestContext:ignoreInheritance:countOnly:nestingLevel:] + 142
    4   CoreData                            0x000000010f4d32e4 -[NSSQLiteAdapter newSelectStatementWithFetchRequestContext:ignoreInheritance:] + 116
    5   CoreData                            0x000000010f670843 -[NSSQLFetchRequestContext _createStatement] + 67
    6   CoreData                            0x000000010f6707de -[NSSQLFetchRequestContext fetchStatement] + 142
    7   CoreData                            0x000000010f6717cb -[NSSQLFetchRequestContext executeRequestCore:] + 27
    8   CoreData                            0x000000010f6db010 -[NSSQLStoreRequestContext executeRequestUsingConnection:] + 208
    9   CoreData                            0x000000010f6af9eb __52-[NSSQLDefaultConnectionManager handleStoreRequest:]_block_invoke + 75
    10  libdispatch.dylib                   0x0000000111cb1db5 _dispatch_client_callout + 8
    11  libdispatch.dylib                   0x0000000111cbfd08 _dispatch_lane_barrier_sync_invoke_and_complete + 132
    12  CoreData                            0x000000010f6af8d0 -[NSSQLDefaultConnectionManager handleStoreRequest:] + 336
    13  CoreData                            0x000000010f6b7504 -[NSSQLCoreDispatchManager routeStoreRequest:] + 308
    14  CoreData                            0x000000010f5ffc38 -[NSSQLCore dispatchRequest:withRetries:] + 232
    15  CoreData                            0x000000010f5fc9ad -[NSSQLCore processFetchRequest:inContext:] + 93
    16  CoreData                            0x000000010f4d27ee -[NSSQLCore executeRequest:withContext:error:] + 574
    17  CoreData                            0x000000010f5e1007 __65-[NSPersistentStoreCoordinator executeRequest:withContext:error:]_block_invoke + 2039
    18  CoreData                            0x000000010f5d9220 -[NSPersistentStoreCoordinator _routeHeavyweightBlock:] + 288
    19  CoreData                            0x000000010f4d1fc0 -[NSPersistentStoreCoordinator executeRequest:withContext:error:] + 1296
    20  CoreData                            0x000000010f4d0295 -[NSManagedObjectContext executeFetchRequest:error:] + 933
    21  Affirmations                        0x000000010dfd8230 $s12Affirmations14UTIAffirmationC6recordACSo8CKRecordC_tcfc + 13072
    22  Affirmations                        0x000000010dfd4f10 $s12Affirmations14UTIAffirmationC6recordACSo8CKRecordC_tcfC + 64
    23  Affirmations                        0x000000010df95584 $s12Affirmations25initDataModelFromCloudKityyFyycfU_ySaySo8CKRecordCGSg_s5Error_pSgtcfU_ + 1252
    24  Affirmations                        0x000000010df8fde6 $sSaySo8CKRecordCGSgs5Error_pSgIeggg_So7NSArrayCSgSo7NSErrorCSgIeyByy_TR + 230
    25  CloudKit                            0x000000010e3cbb0d -[CKQueryOperation _finishOnCallbackQueueWithError:] + 613
    26  CloudKit                            0x000000010e3c4c1a -[CKOperation _finishInternalOnCallbackQueueWithError:] + 582
    27  CloudKit                            0x000000010e3c49ba -[CKOperation _handleCompletionCallback:] + 148
    28  CloudKit                            0x000000010e3cb7e1 -[CKQueryOperation _handleCompletionCallback:] + 197
    29  CloudKit                            0x000000010e43a6c5 __68-[CKOperationCallbackManager _performCallbackForOperation:callback:]_block_invoke + 278
    30  libdispatch.dylib                   0x0000000111cbf725 _dispatch_block_async_invoke2 + 83
    31  libdispatch.dylib                   0x0000000111cb1db5 _dispatch_client_callout + 8
    32  libdispatch.dylib                   0x0000000111cb9225 _dispatch_lane_serial_drain + 778
    33  libdispatch.dylib                   0x0000000111cb9ed0 _dispatch_lane_invoke + 477
    34  libdispatch.dylib                   0x0000000111cc3ea3 _dispatch_workloop_worker_thread + 733
    35  libsystem_pthread.dylib             0x000000011209a611 _pthread_wqthread + 421
    36  libsystem_pthread.dylib             0x000000011209a3fd start_wqthread + 13
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb) 

以下是我的NSManagedObject子类：

public class Affirmation: NSManagedObject {

}

extension Affirmation {

    @nonobjc public class func fetchRequest() -> NSFetchRequest<Affirmation> {
        return NSFetchRequest<Affirmation>(entityName: "Affirmation")
    }

    @NSManaged public var body: String
    @NSManaged public var count: Int64
    @NSManaged public var days: NSData
    @NSManaged public var frequency: Int64
    @NSManaged public var notificationIdentifiers: NSObject
    @NSManaged public var recordName: String?
    @NSManaged public var time: NSDate
    @NSManaged public var timestamp: NSDate
    @NSManaged public var title: String

}

---

您使用的是没有GROUPBY指令的标准查询——错误就是这样说的——所以请使用标准API

request.predicate = predicate

如果指定请求的泛型类型，则可以去掉类型转换和类型注释

let request = NSFetchRequest<Affirmation>(entityName: CoreDataStrings.entityAffirmation)

...

let affirmationEntityInstances = try managedObjectContext.fetch(request)