how to Custom Function Calls in codeigniter

$this->db->call_function();

This function enables you to call PHP database functions that are not natively included in CodeIgniter, in a platform independent manner. For example, lets say you want to call the mysql_get_client_info() function, which is not natively supported by CodeIgniter. You could do so like this: 

$this->db->call_function('get_client_info');

 

You must supply the name of the function, without the mysql_ prefix, in the first parameter. The prefix is added automatically based on which database driver is currently being used. This permits you to run the same function on different database platforms. Obviously not all function calls are identical between platforms, so there are limits to how useful this function can be in terms of portability.

Any parameters needed by the function you are calling will be added to the second parameter.

$this->db->call_function('some_function', $param1, $param2, etc..);

 

Often, you will either need to supply a database connection ID or a database result ID. The connection ID can be accessed using:

$this->db->conn_id;

 

The result ID can be accessed from within your result object, like this:

$query = $this->db->query("SOME QUERY");

$query->result_id;