mysql - Mysql：获取一个表中一个城市出现次数最多的问题

Question

我有一个表，其中包含一些数据和相应的城市、州。我想查看一个城市在特定州的出现次数最多。假设如果有 100 次 Denver,CO 和 10 次 Boulder,CO 出现，我只想看到 Denver，因为这是最大的数字。我尝试了以下方法，但它也列出了所有其他城市：

select state, city, count(city) 
from tab12 
group by city 
order by state, count(city);

任何帮助表示赞赏。谢谢。

Answer 1

SELECT A.* FROM
(
    SELECT city,state,COUNT(1) citycount
    FROM tab12 GROUP BY state,city
) A INNER JOIN
(
    SELECT state,MAX(citycount) citycount FROM
    (SELECT state,city,COUNT(1) citycount
    FROM tab12 GROUP BY state,city) C
) B
USING (state,citycount)
ORDER BY A.state,A.city;

此查询应该适用于拥有多个城市且数量相同的州。

Answer 2

SELECT state, city, max(cnt)
FROM
(select state, city, count(city) as cnt
 from tab12 group by city order by state, count(city))
order by state

如果您还想涵盖可能具有相同频率的城市的情况：

SELECT state, city, count(*) cnt 
FROM cities GROUP BY state,city  
HAVING cnt = (SELECT max(cnt) 
              FROM 
              (SELECT count(*) cnt FROM cities group by state,city) as tbl) 
ORDER BY state;

Answer 3

未经测试，在我脑海中浮现：

select state as thestate, city as thecity, count(*) as thecount
from tab12
group by state, city
having thecount = (
  select max(subcnt)
  from(
    select count(*) as subcnt
    from tab12 sub
    where sub.state = thestate
    group by sub.city
  )
)

请注意，在平局的情况下，这将返回与最高计数并列的每个城市。