How to return an empty string instead of null for $this->input->post()

Hey Guys,

As mentioned in the title, I want to return an empty string because mysql won't let me insert value as NULL. I tried making the following changes from this

PHP Code:

public function post($index = NULL, $xss_clean = NULL)
    {
        return $this->_fetch_from_array($_POST, $index, $xss_clean);
    } 


to this

PHP Code:

public function post($index = "", $xss_clean = NULL)
    {
        return $this->_fetch_from_array($_POST, $index, $xss_clean);
    } 


But it still returns NULL. Any suggestions on how i can do that?

Nevermind guys! I just figured to set the mysql column to NULL

$the_string = (string) $this->input->post('the_string');