MySQL获得最高平均分 [英] MySQL get top average entries

问题描述

我正在尝试编写mysql查询以返回平均课程评分最高的前3门课程.我有两个表格，评分和课程.

I am trying to write a mysql query to return the top 3 courses that have the highest average course rating. I have two tables, Ratings and Courses.

收视率表:

courseId    rating  
   1           6    
   2           2        
   1           4
   2           5
   3           3
   4           0
   6           0

课程表:

courseId        cnum        cname
   1            100         name1
   2            112         name2
   3            230         name3
   4            319         name4
   5            122         name5
   6            320         name6

我需要返回平均评分最高的前三门课程.有什么想法我可以做到这一点吗?谢谢

I need to return the top 3 courses that have the highest average rating. Any ideas how I could do this? Thanks

推荐答案

SELECT Courses.*
FROM   Courses NATURAL JOIN (
  SELECT   courseId, AVG(rating) avg_rating
  FROM     Ratings
  GROUP BY courseId
  ORDER BY avg_rating DESC
  LIMIT    3
) t

在 sqlfiddle 上查看.

这篇关于MySQL获得最高平均分的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！