如何加入两个表用户名和消息表

2 回答

• 0

  我认为就像这样：

  SELECT u.username, m.msg
  FROM users u
  INNER JOIN msg m ON m.user_id = u.user_id
  

  应该可以

  回复于 2024-04-25T23:26:51+08:00
• 0

  您需要使用PDO或mysqli扩展来进行数据库操作 .

  你的查询应该是

  SELECT username, msg FROM msg JOIN users ON msg.user_id = users.user_id
  

  ---

  使用PDO的示例：

  $host = '127.0.0.1';
  $db   = 'test';
  $user = 'root';
  $pass = '';
  $charset = 'utf8';
  
  $dsn = "mysql:host={$host};dbname={$db};charset={$charset}";
  $opt = [
      PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
      PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
      PDO::ATTR_EMULATE_PREPARES   => false,
  ];
  $pdo = new PDO($dsn, $user, $pass, $opt);
  
  $stmt = $pdo->prepare('SELECT username, msg FROM msg JOIN users ON msg.user_id = users.user_id');
  $stmt->execute();
  $usersMessages = $stmt->fetchAll(PDO::FETCH_ASSOC);
  

  回复于 2024-04-25T23:26:51+08:00