I am trying to make a search box which will take three parameters and will list all the products related to them. But the like wild card is not working. My code is as follow:

```
public function search($textstring,$category,$college,$limit,$offset){
  $sql = "SELECT * FROM ads WHERE Category = ? AND College_id = ? AND 
        AdTitle = ?";

        $query = $this->db->limit($limit,$offset)
                          ->query($sql,array($category,$college,'%'.$textstring.'%'));
        echo"<pre>";
        print_r($query);
        print_r($textstring);
        echo"</pre>";              

         return $query->result_array();
     }

```

when I search for college and category parameter it works but when I include text string it is not working