objective c - Fetch the smallest date of an object in CoreData -

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I am facing the same problem, but @Deidelong's answer is not working for me

To get a small date in the set of objects, I get the following error 

  - [NSDT count]: An unspecified selector was sent for example  
>  
 My understanding is that  NSExpression  's max: support only  NSArray  s so I need another solution.  
 @Deidelong suggested to use the ascending  nssort descriptor , and I did this:  
  NSFetchRequest * fetchRequest = [[NSFetchRequest alloc ] Init]; FetchRequest.entity = [NSEntityDescription EntityForName: Managed object contexts in NSStringFromClass ([GCSession class]): self.objectContext]; FetchRequest.fetchLimit = 1; NSSortDescriptor * sort = [[NSSortDescriptor alloc] initWithKey: @ "startDate" ascending: yes]; FetchRequest.sortDescriptors = [NSArray arrayWithObject: sort]; GCSession * session = [[self.objectContext executeFetchRequest: fetchRequest error: zero] lastObject]; Return Session Start; The problem here is that the  session  returned from Fetcher does not appear with the smallest  start date . In my tests, it seems that it has also returned the  latest  date but it does not seem to consistently.  
 I also sort every  GCSession  object and sort it but it seems that in the above manner, especially the  GCSession  number will increase when the user app Will use.  
  edit : bug in example code of apple   
 
 
 After the object is brought in only one way it comes in the game you set a fetch limit of one And there is no prediction that "move any random single GCSession object". An array 1 element is long to fetch one, then it changes it, which is useless.  
 If you want to use a type to find a minimum or maximum, then you have to get all the items and then sort them into them. Removing the line:  
  fetchRequest.fetchLimit = 1;   
 one ?? | The code should be allowed to work  
 However, you should be able to get the minimum and maximum value with expressions. This is a basic operation.  
 EDIT: Look at the comments for more details but the example of the applet can work if you change the backing store to SQL instead of XML

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