mysql - 计算

Question

我想返回简单计算的结果，但我不确定如何执行此操作。我的表如下：

SELECT 
    COUNT(fb.engineer_id) AS `total_feedback`, 
    SUM(fb.rating) AS `total_rating`, fb.engineer_id 
FROM 
    `feedback` AS fb 

现在，当我返回的结果我用PHP使calulation，但现在我要订购的结果（这个查询嵌套在一个更大的一个）的结果。

的计算如下：

$p = ((($total_rating*20)*$total_feedback)/10); 

可这在初始查询做些什么呢？

Answer 1

你可以做

SELECT 
    COUNT(fb.engineer_id) AS `total_feedback`, 
    SUM(fb.rating) AS `total_rating`, fb.engineer_id 
FROM 
    `feedback` AS fb 
ORDER BY total_rating*20*total_feedback/10 

，或者如果你想在你的结果列：

SELECT 
    COUNT(fb.engineer_id) AS `total_feedback`, 
    SUM(fb.rating) AS `total_rating`, fb.engineer_id 
    total_rating*20*total_feedback/10 AS p 
FROM 
    `feedback` AS fb 
ORDER BY p 

Answer 2

您的查询没有groub by条款，所以它只是返回一行，那么你怎么了想要订购你的结果？