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  

执行此查询时，输出为：

5.0000  
4.7500  
4.5000  
5.0000  
4.0000  
4.0000

我的评分栏是int(10)。

Answer 1

您必须按AVG(rating)订购，而不是rating

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

在您的情况下，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