未定义的索引：user_name

Question

当我尝试使用$ _SESSION中的user_name时，我收到错误

  

＆＃39;未定义的索引：user_name＆＃39;

CODE：

  $_SESSION['signed_in'] = true;

  while ($row = $query1->fetch(PDO::FETCH_ASSOC))
  {
    $_SESSION['user_id']    = $row['user_id'];
    $_SESSION['user_name']  = $row['user_first_name'];
  }

  echo 'Welcome, ' . $_SESSION['user_name'] . '. <a href="index.php">Proceed to the overview page to see your tasks</a>.';  

Answer 1

添加session_start（）;在页面顶部开始会话。