按出现次数计数

Question

我是类似下面的查询：

select * from combined where valid_rating is null
order by FIND_IN_SET(provider, (select provider from combined where valid_rating is null group by provider order by count(1) desc))

基本上，我尝试先按“最重要”

provider

（项目数最多的）进行排序。我如何使用

order_by

中的表达式正确执行此操作，甚至可能使用窗口函数？

Answer 1

加入返回计数的子查询，然后按计数排序。

SELECT c.*, ct.count
FROM combined AS c
JOIN (
    SELECT provider, COUNT(*) AS count
    FROM provider
    GROUP BY provider
) AS ct ON c.provider = ct.provider
ORDER BY count DESC