OOP php method - pass parameters in or get from inside object

I am new to OOP and have written a products class. All is working fine but I am unsure which of the below version of a method within this class is best?

The first gets the variables from within the object and the second passes the variables into the class. Both work. I originally had it as the first version but things seems to be running slow and then changed it to the second.

public function getProductURLstart(){  
    $select = "SELECT l.URL, p.id FROM logins AS l
        INNER JOIN Pages AS p ON l.id = p.clientID 
        WHERE l.id = '$this->skID' AND p.productPage = 1";

    $res = mssql_query($select);
    $r = mssql_fetch_row($res);     

    $url = trim($r[0]); 
    $page_id = $r[1];

    return  $url .'/index.aspx?pageID='. $page_id . '&prodID=$this->prodID';
}

OR

static function getProductURLstart($skID, $prodId){    
    $select = "SELECT l.URL, p.id FROM logins AS l
        INNER JOIN Pages AS p ON l.id = p.clientID 
        WHERE l.id = '$skID' AND p.productPage = 1";

    $res = mssql_query($select);
    $r = mssql_fetch_row($res);     

    $url = trim($r[0]); 
    $page_id = $r[1];

    return  $url .'/index.aspx?pageID='. $page_id . '&prodID=$prodId';
}