Mysql 如何写正确的顺序。。。SQL选择中的描述？

你好

检查表的结构

我想选择：

select `idn` order by sum DESC,
where sum = (value amount where type = marks and status = up) - (value amount where type = marks and status = down)

为此，我使用SQL：

select idn from Balans as outerB WHERE idn ! = '' group by idn order by 
ifnull((select sum(innerB.amount) from Balans as innerB 
    where innerB.idn = outerB.idn 
    and type='up'), 0) -
ifnull((select sum(innerB.amount) from Balans as innerB 
    where innerB.idn = outerB.idn 
    and type='down'), 0) DESC
limit 5

但是在SQL中，不按顺序进行正确的排序。。。描述

例如，在我的示例中，结果应该是：

187113012

6299927

可以找到测试SQL

---

请告诉我如何编写正确的SQL select？

如何使用

CASE

  SELECT idn,
         (SUM(CASE WHEN type = 'marks' AND status = 'up' THEN amount ELSE 0 END)-
         SUM(CASE WHEN type = 'marks' AND status = 'down' THEN amount ELSE 0 END)) 
         AS result
    FROM Balans b
   WHERE idn != ''
GROUP BY idn
ORDER BY result DESC
   LIMIT 5;

---

<强>

> P>如果您愿意考虑对数据库结构的更改，我建议将该值存储为一个正值，如果状态为“UP”，则为正值，如果状态为“下降”，则为负值。 在这些条件下，您的查询会简单得多

SELECT idn, SUM(amount) as total
FROM Balans as outerB 
WHERE idn !='' AND type = 'marks'
GROUP BY idn 
ORDER BY total desc
LIMIT 5

但是，请注意，这不会返回表中没有任何“标记”的记录。如果您需要支持这一点，那么我认为您可以重新使用

案例

操作，类似于Prix答案中的查询