NSPredicate concatenating attributes

I m trying to figure out how to concatenate attribute names. I have a county and a district attribute that I want to query like

[NSPredicate predicateWithFormat:@"county + district contains[cd] %@",searchBar.text]

gives me unimplemented SQL generation for predicate error. and开发者_StackOverflow I am not sure how to implement NSPredicate. Thanks

This should give you an idea of how to do some more complicated searching. It will match queries for "county district", "district county", etc.

    NSArray *searchTerms = [searchBar.text componentsSeparatedByString:@" "];
    NSString *predicateFormat = @"(county contains[cd] %@) OR (district contains[cd] %@)";
    NSPredicate *predicate;
    if ([searchTerms count] == 1) {
        NSString *term = [searchTerms objectAtIndex:0];
        predicate = [NSPredicate predicateWithFormat:predicateFormat, term, term];
    } else {
        NSMutableArray *subPredicates = [NSMutableArray array];
        for (NSString *term in searchTerms) {
            NSPredicate *p = [NSPredicate predicateWithFormat:predicateFormat, term, term];
            [subPredicates addObject:p];
        }
        predicate = [NSCompoundPredicate andPredicateWithSubpredicates:subPredicates];
    }
    [fetchRequest setPredicate:predicate];

See Cocoa Is My Girlfriend: Adding iTunes-style search to your Core Data application for more explanation.

I ended up implementing another field as concatenating the two variables(district+country) and perform the query on that variable.

I did something similar and concluded that like cekisakurek, the best method was to concatenate the fields into a common field (more relevant for first/last name)

- (NSString *)fullName {
    return [NSString stringWithFormat:@"%@ %@", self.firstName, self.lastName];
}

and then filtered on this field using 'contains[cd]'

[NSPredicate predicateWithFormat:@"fullName contains[cd] %@", self.searchBar.text];

[NSPredicate predicateWithFormat:@"county contains[cd] %@ AND district contains[cd] %@",searchBar.text,searchBar.text];

Just try the above lines of code, it would helps you.