Question

我正在尝试更新表格中的值：

+----+-------------+
| Id | Value       |
+----+-------------+
| 1  | title       |
+----+-------------+
| 2  | description |
+----+-------------+
| 3  | email       |
+----+-------------+
| 4  | keywords    |
+----+-------------+

如果PK已存在，我想更新值，否则插入新行。

submit.php：

include('../../include/config.php');

if($_POST['settings']){
    $title=$_POST['title'];
    $description=$_POST['description'];
    $email=$_POST['email'];
    $keywords=$_POST['keywords'];

    $test=$db->query("UPDATE `settings` SET `value` = '$title' WHERE `id` =1, SET `value` = '$description' WHERE `id` =2,SET `value` = '$email' WHERE `id` =3, SET `value` = '$keywords' WHERE `id` =4;");
    if($test){
        echo "good";
    }else{
        echo "bad";
    }

}

更新

对于现在阅读此问题的人，请勿使用此结构来存储您的网站设置。我不建议使用查询，因为它易受SQL注入

Answer 1

考虑这个例子......

SELECT * FROM user;
+---------+------+
| user_id | name |
+---------+------+
|       1 | X    |
|       2 | B    |
|       3 | C    |
+---------+------+

UPDATE user 
   SET name = CASE user_id WHEN 1 THEN 'A' 
                           WHEN 2 THEN 'J' 
                           WHEN 3 THEN 'K' END;

SELECT * FROM user;
+---------+------+
| user_id | name |
+---------+------+
|       1 | A    |
|       2 | J    |
|       3 | K    |
+---------+------+

Answer 2

只要您在Id字段中有唯一索引或主键，此查询实际上可以使用Mysql中的单个语句完成。

INSERT INTO `settings` (`id`,`value`) VALUES (1,?),(2,?),(3,?),(4,?)
  ON DUPLICATE KEY UPDATE `value`=VALUES(`value`);

请参阅https://dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html

上 INSERT ... ON DUPLICATE KEY 的文档

更新多行中的一列

2 个答案: