Sqlite how to check all contains about one table

Hello my question is about iOS + SQLite.

I've built one application in iOS easy. I have one screen where I have 11 textfield and I want to check if exists one name in one table of database, namely, if one registry of table exist in this table.

- (IBAction)checkRegistry:(id)sender {
    NSString *query = [NSString stringWithFormat:@"select * from players"]
    // i don't know that to make this check ....
}