Question

学生回来了。谢谢你帮助耐心;）

我正在使用这样的foreach循环：

foreach ($value as $val)
{
//coming from database, from a select query:
$points = $row['points'];  

//now I want to update another database table:  
 $sql = "update user set totalpoints=".$points." where userid=".$uid." ";

//but by doing this, table user is updated with the value of $points in the last iterarion 

}

如何使用$ points的总和而不是上次迭代的值来更新表格，我该怎么做？

再次感谢

Answer 1

不是100％肯定，但似乎你想要：

$sum = 0;

foreach ($value as $val) {
    $sum += $row['points'];  
}

$sql = "update user set totalpoints=".$sum." where userid=".$uid;

Answer 2

$points = 0;
while ($row = mysq_fetch_array()) // from where you are getting row
{
//coming from database, from a select query:
$points += $row['points'];  

}


//now I want to update another database table:  
 $sql = "update user set totalpoints=".$points." where userid=".$uid." ";

Answer 3

您应该在一个查询中完成所有操作

我认为您的原始查询类似于SELECT * FROM matches WHERE userid='$uid'（无论如何），所以请执行类似UPDATE user SET totalpoints=(SELECT SUM(points) FROM matches WHERE userid='$uid' GROUP BY userid) WHERE userid='$uid'的操作（可能它不适合您的确切问题，但我希望您能得到这个想法）

PHP：循环内部需要求和

3 个答案: