// Create a SQL statement to query the data we're looking for.
$namesql = "SELECT fname, lname FROM $user_tbl WHERE
    username = '$_SESSION[user]'";

// Perform the query, return the data, store it in the varible $namerows.
$namerows = $conn->query ( $namesql );

// Use the date to construct a real name.
$row = $namerows->fetch (PDO::FETCH_ASSOC);
$realname = "{$row['lname']}, {$row['fname']}";