php - 使用PDO和MySQL更新查询

我只想用PDO编写更新查询，但我无法执行代码？

try {
 $conn = new PDO("mysql:host=$hostdb; dbname=$namedb", $userdb, $passdb);
$conn->exec("SET CHARACTER SET utf8");      // Sets encoding UTF-8
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

 $sql = "UPDATE `access_users`
      (`contact_first_name`,`contact_surname`,`contact_email`,`telephone`)
      VALUES (:firstname, :surname, :telephone, :email);
      ";



 $statement = $conn->prepare($sql);
 $statement->bindValue(":firstname", $firstname);
 $statement->bindValue(":surname", $surname);
 $statement->bindValue(":telephone", $telephone);
 $statement->bindValue(":email", $email);
 $count = $statement->execute();

  $conn = null;        // Disconnect
}
catch(PDOException $e) {
  echo $e->getMessage();
}

最佳答案

您的UPDATE语法错误
您可能打算更新一行而不是全部更新，因此必须使用WHERE子句来定位您的特定行


更改

UPDATE `access_users`
      (`contact_first_name`,`contact_surname`,`contact_email`,`telephone`)
      VALUES (:firstname, :surname, :telephone, :email)

至

UPDATE `access_users`
   SET `contact_first_name` = :firstname,
       `contact_surname` = :surname,
       `contact_email` = :email,
       `telephone` = :telephone
 WHERE `user_id` = :user_id -- you probably have some sort of id