php - Mysql - 选择具有最高平均值的不同客户端代码

Question

我有一个 mysql 表，其中存储了客户端的星级，所以：

参考，客户代码，日期，评论，星星

相同的客户端代码可以出现多次。

我需要选择具有最高平均星数的不同客户端代码。任何建议如何得到这个

Answer 1

SELECT
    t1.clientcode clientcode,
    t2.sum sum,
    t3.count count,
    CASE t3.count WHEN 0 THEN 0 ELSE t2.sum / t3.count END average
FROM
    t1
    LEFT JOIN
    (
        SELECT
            clientcode, 
            SUM(stars) sum
        FROM t1
        GROUP BY clientcode
    ) t2 ON t1.clientcode = t2.clientcode
    LEFT JOIN
    (
        SELECT
            clientcode, 
            COUNT(stars) count
        FROM t1
        GROUP BY clientcode
    ) t3 ON t1.clientcode = t3.clientcode

Answer 2

Please try query given below.

select avg(`stars`) AS `avgstar` ,`clientcode`  from `t1` group by `clientcode` order by `avgstar` DESC

Here group by clientcode will be get record for every distinct clientcode and order by avgstar where avgstar is average of stars field value for each clientcode in Descinding order.

thanks

Answer 3

这将显示不同客户端代码的星级平均值

SELECT avg(stars) from t1 group by clientcode;

Answer 4

SELECT 
    t1.* 
FROM 
    table t1 
WHERE 
    t1.stars IN 
    (
        SELECT 
            MAX(t2.stars) 
        FROM 
            table t2 
        WHERE  
            t2.clientcode = t1.clientcode
    )