如何通过nspredicate date过滤SQL结果？

Question

我想按日期过滤sql lite数据库结果，但我很糟糕在ios日期和时间对象，并不确定如何做到这一点。您如何设置NSPredicate以在今天，过去7天，过去30天和过去90天过滤结果？

感谢

Answer 1

例

- (NSPredicate *)predicateForDateWithinLast30Days 
{ 

    NSDate *currentDate = [NSDate date];// get the current date 


    // get the date 30 days prior to current date 

    NSCalendar *calendar = [NSCalendar currentCalendar]; 
    NSDateComponents *dateComps = [[NSDateComponents alloc] init]; 
    [dateComps setDay:-30]; 
    NSDate *date30DaysAgo = [calendar 
      dateByAddingComponents:dateComps 
      toDate:currentDate options:0]; 

    // create the predicate 
    NSPredicate *last30DaysPredicate = [NSPredicate 
      predicateWithFormat:@"dateToCompare > %@", date30DaysAgo]; 

    return last30DaysPredicate; 
}