MySQL ORDER BY 十进制值不起作用

Question

带有 order by 子句的 SQL 查询无法正常工作。

VALUES:
5.0000   
4.0000   
4.5000  
4.7500  
4.0000  
5.0000

查询:

SELECT  AVG(rating) as rating
FROM review
GROUP BY id
ORDER BY CAST(`rating` as signed) DESC  

当我执行这个查询时，输出是:

5.0000  
4.7500  
4.5000  
5.0000  
4.0000  
4.0000

我的评级列是 int(10)。

Answer 1

您必须按 AVG(rating) 而不是 rating

SELECT AVG(rating) as rating FROM review GROUP BY id ORDER BY AVG(rating) DESC 

在您的例子中，别名和列具有相同的名称。为了避免混淆，你可以这样做:

SELECT AVG(rating) as avgrating FROM review GROUP BY id ORDER BY avgrating DESC