NSError *error;
NSManagedObjectContext *context = [(AppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext];
NSEntityDescription *entityDesc = [NSEntityDescription entityForName:@"Tz_task_from" inManagedObjectContext:context];
NSFetchRequest *request = [[NSFetchRequest alloc]init];
[request setEntity:entityDesc];
[request setReturnsObjectsAsFaults:NO];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"taskfrom=%@",userid];
[request setPredicate:predicate];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"taskend" ascending:NO];
NSArray*sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor,nil];
[request setSortDescriptors:sortDescriptors];
NSArray *objects = [context executeFetchRequest:request error:&error];
1恋追、比較運(yùn)算符>,<,==,>=,<=,!=
2、范圍運(yùn)算符：IN惋嚎、BETWEEN
3海铆、字符串本身:SELF
4揍很、字符串相關(guān)：
（1）淑掌、CONTAINS包含某個字符串
@nameCONTAINS[cd] %@
（2）榆芦、BEGINSWITH以某個字符串開頭
@nameBEGINSWITH[c] %@
（3）谭溉、ENDSWITH以某個字符串結(jié)束
@nameENDSWITH[d] %@
注:
[c]不區(qū)分大小寫
[d]不區(qū)分發(fā)音符號即沒有重音符號
[cd]既不區(qū)分大小寫，也不區(qū)分發(fā)音符號匕积。
5盈罐、通配符：LIKE
例：[NSPredicate predicateWithFormat:[NSString stringWithFormat:@"customername LIKE[cd] '*%@*'",_searchString]];
6、正則表達(dá)式：MATCHES
例：NSString *regex = @"^A.+e$";? //以A開頭闪唆，e結(jié)尾
@"name MATCHES %@",regex
