Fatal error: Call to a member function close() on a non-object. MySQLi issue

Question

I have been getting the following error when I uploaded to a live server. It works OK on localhost which I thought was strange.

Fatal error: Call to a member function close() on a non-object....

The line it refers to

$stmt->close();

The connection to the DB

$connection=new mysqli($MYSQL_HOST,$MYSQL_USER,$MYSQL_PASS,$DB)or die(mysqli_error($connection));

The class itself.

function getTimes(){ //this method just pulls the results of the query and returns them as an array
    global $connection;
    $route = $this->route;
    $station = $this->station;
    $day = $this->day;

    // create a prepared statement
    if ($stmt = $connection->prepare("select time from timetable where route=? and day=? and station=?")) {
        $stmt->bind_param("sss", $route, $day, $station);   // bind parameters for markers
        $stmt->execute();   //execute query             
        $stmt->bind_result($col1);  //bind result variables
        while ($stmt->fetch()){
            $results[]=$col1;
        }
    }
    $stmt->close();//close statement
    return $results;
}

Answer 1

You should put $stmt into you if clause. There is a possiblity that if (false) and still get to your $stmt->close();

Answer 2

Your problem was that the $stmt object was instantiated as part of an if condition test. In the cases it failed, i.e. when it returns false, you were still trying to call ->close() on it anyway. I moved the method call within the if block.

Now you need to add an else clause to handle the fact that your script couldn't prepare the statement and given you say this works locally but not on your live server, I suggest there is some configuration difference causing a problem here. You need to turn on error handling with display_errors('1') and error_reporting(E_ALL). Don't forget to turn these off before letting the world at your new script. :)

function getTimes(){ //this method just pulls the results of the query and returns them as an array
        global $connection;
        $route = $this->route;
        $station = $this->station;
        $day = $this->day;

        // create a prepared statement
        if ($stmt = $connection->prepare("select time from timetable where route=? and day=? and station=?")) {
            $stmt->bind_param("sss", $route, $day, $station);   // bind parameters for markers
            $stmt->execute();   //execute query             
            $stmt->bind_result($col1);  //bind result variables
            while ($stmt->fetch()){
                $results[]=$col1;
            }
            $stmt->close();//close statement
        }

        return $results;
    }