php - MySQL中的行值增加和减少1

Question

您好，我有一个 MySQL 数据库表“点”，用户可以单击一个按钮，并且应该从他们的帐户中删除一个点，他们按下的按钮具有另一个用户的 ID，因此他们的帐户必须增加一个。

我让它在 jQuery 中工作并检查了 Firebug 中的变量/帖子，它确实发送了正确的数据，例如:

userid= 1 
posterid = 4

我认为问题出在我的 PHP 页面上:

<?php


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

$userid=mysql_real_escape_string($_POST['user_id']);
$posterid=mysql_real_escape_string($_POST['poster_id']);

if (loggedin()) 
{
include ('../connection.php');
$query1 = "UPDATE `points` SET `points` = `points` - 1 WHERE `userID` = '$userid'";
$result1=mysql_query($query1);


$query2 = "UPDATE `points` SET `points` = `points` + 1 WHERE `userID` = '$posterid'";
$result2=mysql_query($query2);


if ($result1 && result2)
{
    echo "Successful";  
    return 1;
}
else
{

    echo mysql_error();
    return 0;   
}
}
?>

有什么想法吗？谢谢:)

Answer 1

不需要增加/减少字段值的两个查询:

mysql_query("UPDATE table SET field = field + 1 WHERE id = $number");

是一个完全有效的查询，如下所示:

mysql> describe points;
+--------+---------+------+-----+---------+-------+
| Field  | Type    | Null | Key | Default | Extra |
+--------+---------+------+-----+---------+-------+
| uid    | int(11) | NO   | PRI | NULL    |       |
| points | int(11) | YES  |     | 0       |       |
+--------+---------+------+-----+---------+-------+
2 rows in set (0.05 sec)

mysql> insert into points VALUES (1,0),(2,0);
Query OK, 2 rows affected (0.14 sec)

mysql> select * from points;
+-----+--------+
| uid | points |
+-----+--------+
|   1 |      0 |
|   2 |      0 |
+-----+--------+
2 rows in set (0.05 sec)

mysql> update points set points = points+1 where uid = 1;
Query OK, 1 row affected (0.27 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from points;
+-----+--------+
| uid | points |
+-----+--------+
|   1 |      1 |
|   2 |      0 |
+-----+--------+
2 rows in set (0.00 sec)

经过测试，你确定你进入了 if (loggedin()) 子句吗？

我必须同意 KM，很高兴看到 echo $query1; 或 echo $query2;