Multiple database- access data from the 3rd database using codeigniter - database

Question

I am using codeigniter.I want to use 3 database in my project.I set the database.php file us,
$active_group = 'default';
$active_record = TRUE;
$db['default']['hostname'] = 'localhost';
$db['default']['username'] = 'marketer_fp';
$db['default']['password'] = 'xxxxx';
$db['default']['database'] = 'marketer_fpr';
$db['default']['dbdriver'] = 'mysql';
$db['default']['dbprefix'] = '';
$db['default']['pconnect'] = TRUE;
$db['default']['db_debug'] = TRUE;
$db['default']['cache_on'] = FALSE;
$db['default']['cachedir'] = '';
$db['default']['char_set'] = 'utf8';
$db['default']['dbcollat'] = 'utf8_general_ci';
$db['default']['swap_pre'] = '';
$db['default']['autoinit'] = TRUE;
$db['default']['stricton'] = FALSE;
$db['wpdb']['hostname'] = "localhost";
$db['wpdb']['username'] = "marketer_fprr";
$db['wpdb']['password'] = "yyyy";
$db['wpdb']['database'] = "marketer_mark";
$db['wpdb']['dbdriver'] = "mysql";
$db['wpdb']['dbprefix'] = "";
$db['wpdb']['pconnect'] = FALSE;
$db['wpdb']['db_debug'] = TRUE;
$db['wpdb']['cache_on'] = FALSE;
$db['wpdb']['cachedir'] = "";
$db['wpdb']['char_set'] = "utf8";
$db['wpdb']['dbcollat'] = "utf8_general_ci";
$db['wpfashn']['hostname'] = "localhost";
$db['wpfashn']['username'] = "marketer_fprr";
$db['wpfashn']['password'] = "yyyy";
$db['wpfashn']['database'] = "marketer_fah";
$db['wpfashn']['dbdriver'] = "mysql";
$db['wpfashn']['dbprefix'] = "";
$db['wpfashn']['pconnect'] = FALSE;
$db['wpfashn']['db_debug'] = TRUE;
$db['wpfashn']['cache_on'] = FALSE;
$db['wpfashn']['cachedir'] = "";
$db['wpfashn']['char_set'] = "utf8";
$db['wpfashn']['dbcollat'] = "utf8_general_ci";
The second and third database have same username and password.
In the controller ,inside construct function these 3 database are called.
$this->db3 =$this->load->database('wpfashn', TRUE);
$this->db2 =$this->load->database('wpdb', TRUE);
$this->db =$this->load->database('default', TRUE);
Inside another function a query is written,which should be executed by using the database 3.
$check=$this->db3->query("select * from mm_use_dat where wp_user_id='2'");
print_r($check->result());
this query return an empty array even if value present in the database.What should be the problem?Please help me to find a solution!