更新数量 <=0 设置信用的用户

Question

$check_empty_user = $DBcon->query("SELECT * FROM bubble_spends where a_amount <= 0");
$count=$check_empty_user->num_rows;
$username23=$DBcon->query("SELECT a_name FROM bubble_spends where a_amount <= 0 LIMIT 1");

$count2=$username23->fetch_array;

 if (!$count==0) {

  $DBcon->query("DELETE FROM bubble_spends where a_amount <= 0");
  $DBcon->query("UPDATE users SET credits = credits+100000 WHERE username='$count2'");
        echo "user has been outspended";
    }

主要目的是通过它实现，当一个bubble_spend的金额小于0时，应该从bubble花费中选择a_name，然后更新users set credits=credits+10 where username=$a_name

但这不起作用，我忙了 2 个小时，我无法修复

Answer 1

您正在尝试获取 bubble_spends 表中数量小于 0 的所有用户，然后从该表中执行删除并在另一个表上进行更新。

要做到这一点，简单的方法是从bubble_spends表中获取数量小于0的所有名称，然后使用IN运算符加上内部查询来更新它们。更新后，您可以从另一个表中删除它们。

$DBcon->query("UPDATE users SET credits = credits+100000 
WHERE username IN (SELECT a_name FROM bubble_spends where a_amount <= 0)");

$DBcon->query("DELETE FROM bubble_spends where a_amount <= 0");

应该这样做。