Ios 解析关系数据的查询没有使用orderedByAscending按顺序返回

我正在查询parse上的关系数据，我希望对象按照创建日期的顺序返回。我以前使用过这种方法，但无法使用关系数据获得有序查询。查询返回的顺序是随机的。提前谢谢！这是我的密码：

    PFQuery *postQuery = [PFQuery queryWithClassName:@"Post"];
    [roomQuery whereKey:@"name" equalTo:self.postName];

    NSError *error;
    //done on main thread to have data for next query
    NSArray *results = [postQuery findObjects:&error];

    PFObject *post;

    if ([results count]) {
        post = [results objectAtIndex:0];
        NSLog(@"results were found");
    } else {
        NSLog(@"results were not found");
    }

    PFRelation *commentsRelation = [@"Comments"];
    [commentsRelation.query orderByAscending:@"createdAt"];
    [commentsRelation.query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (error) {
            NSLog(@"Error Fetching Comments: %@", error);
        } else {
            NSArray *comments = objects; 
     }

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我对你的代码有点困惑

您创建了一个“postQuery”，并调用它，但从不使用它的任何数据

还有一个roomQuery似乎从未被分配或使用过

您正在按其名称查询特定帖子。你在控制它的名字吗？如果没有，您应该使用id

什么是PFRelation commentsRelation=[@“Comments”] 可能是因为它只是一个片段，这些东西是在别处处理的；但是，对于我的答案，我假设您的“comments”字段是一个“Comment”类对象数组

备选案文1：

PFQuery * postQuery = [PFQuery queryWithClassName:@"Post"];
[postQuery whereKey:@"name" equalTo:self.postName]; 
// again, possibly an id field would be more reliable
// [postQuery whereKey:@"objectId" equalTo:self.postId];
[postQuery includeKey:@"Comments"];
PFObject * post = [postQuery getFirstObject];// no need to download all if you just want object at [0]
// this will contain your post and all of it's comments with only one api call
// unfortunately, it's not sorted, so you would have to run a sort.
NSArray * comments =  [post[@"Comments"] sortedArrayUsingComparator: ^(id obj1, id obj2) {
    return [obj1[@"createdAt" compare: obj2[@"createdAt"];
}];

备选案文2：

也许更好的选择是修改您的数据结构，而不是将评论与文章相关联，您可以将文章与评论相关联（如在解析文档中）

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上述两种解决方案都避免了进行额外的不必要的api调用（毕竟是基于调用的解析费用！）。

只要阅读代码，我就看不出有任何错误。你能给我们看一个注释中的数据示例吗？“PFRelation*commentsRelation=[@“comments”]；”这段代码甚至不应该编译，你能修复它以显示如何获得注释关系吗？

PFQuery * postQuery = [PFQuery queryWithClassName:@"Post"];
[postQuery whereKey:@"name" equalTo:self.postName]; 
// again, possibly an id field would be more reliable
// [postQuery whereKey:@"objectId" equalTo:self.postId];

PFQuery * commentQuery = [PFQuery queryWithClassName:@"Comment"];
[commentsQuery whereKey:@"parent" matchesQuery:postQuery]; // when creating a comment, set your post as its parent
[commentsQuery addOrderDescending:@"createdAt"]
[commentQuery findObjectsInBackgroundWithBlock:^(NSArray *comments, NSError *error) {
    // comments now contains the comments for myPost
}];