while循环打印两次输出

Question

在我的代码中，while循环打印两次输出。这是我的PHP代码：

if($con) 
{
    echo '<h1>Connected to MySQL</h1>';
    $sql = 'select age, salary from emp';
    mysql_select_db('toor');
    $retval = mysql_query($sql, $con);

    if(!$retval)
        die('could not get data'.mysql_error());

    while($row = mysql_fetch_array($retval, MYSQL_NUM))
    {
        echo "age:{$row[0]}<br>"."sal:{$row[1]}<br>";
    }
}

Answer 1

替换
$row = mysql_fetch_array($retval, MYSQL_NUM)
  与
$row = mysql_fetch_array($retval)

并从$con

中删除mysql_query()