Stackmob SMQuery OR conditioning："Sort不能与OR语句一起使用stackmob“

Question

我正在使用Stackmob SMQuery，并尝试使用4个OR条件进行查询，并对所有结果进行排序。我的代码如下。问题是

        SMQuery *query = [[SMQuery alloc] initWithSchema:STACKMOB_SCHEMA_TESTIMONIAL];

        [query where:@"friend_id" isIn:[friendFacebookIds arrayByAddingObject:[KKKeychain getStringForKey:@"facebookId"]]];

        // WHERE (privacy == Public OR (privacy == Private AND friend_id == myFacebookId) OR (privacy == Restricted AND myFacebookId NOT IN restricted_Ids))

        SMQuery *subQuery0 = [[SMQuery alloc] initWithSchema:STACKMOB_SCHEMA_TESTIMONIAL];
        SMQuery *subQuery1 = [[SMQuery alloc] initWithSchema:STACKMOB_SCHEMA_TESTIMONIAL];
        SMQuery *subQuery2 = [[SMQuery alloc] initWithSchema:STACKMOB_SCHEMA_TESTIMONIAL];
        SMQuery *subQuery3 = [[SMQuery alloc] initWithSchema:STACKMOB_SCHEMA_TESTIMONIAL];

        [subQuery0 where:@"privacy" isEqualTo:nil]; // just in case no privacy was set, assume it is public
        [subQuery0 orderByField:@"createddate" ascending:NO];

        [subQuery1 where:@"privacy" isEqualTo:[NSNumber numberWithInt:TTPrivacyLevelPublic]];
        [subQuery1 orderByField:@"createddate" ascending:NO];

        [subQuery2 where:@"privacy" isEqualTo:[NSNumber numberWithInt:TTPrivacyLevelPrivate]];
        [subQuery2 where:@"user_id" isEqualTo:[KKKeychain getStringForKey:@"facebookId"]]; // for private post, I can only see posts that were created by me
        [subQuery2 orderByField:@"createddate" ascending:NO];

        [subQuery3 where:@"privacy" isEqualTo:[NSNumber numberWithInt:TTPrivacyLevelRestricted]];
        [subQuery3 where:@"restricted_user_ids" isNotEqualTo:[KKKeychain getStringForKey:@"facebookId"]]; // make sure I'm not restricted to see
        [subQuery3 orderByField:@"createddate" ascending:NO];

        // combine subquery to main query

        [query and:[[[subQuery1 or:subQuery2] or:subQuery3] or:subQuery0]];

        [query orderByField:@"createddate" ascending:NO];
        ....

因此，如果我注释了最后一行"query orderByField:@"createddate“createddate:NO；”，那么它工作得很好。但是，结果将是4个不同数据集的组合，而不是按创建顺序排序。我还尝试在每个子查询中排序，但结果也是不正确的，因为它们只在每个子查询中排序，而不是与其他结果组合。

谢谢。

Answer 1

数据库不支持执行同时包含OR和排序的查询-这是数据库限制。相反，在StackMob上执行查询，然后使用sortedArrayUsingComparator或类似的方法按createddate对结果进行本地排序。