mysql - sql 中最常出现的值

Question

我在这里创建了一个示例表:https://dbfiddle.uk/wUvTIsyN

我正在尝试使用分组依据查询最常出现的值。这是我的尝试:

select pid, propName, Address, City, Response, count(Response) as cr
from Prop
group by 
        pid,
        propName,
        Address,
        City,
        Response
order by
      cr
limit 1;

预期输出:

pid propName    Address City    Response

1   p1  addr1   c1  2
2   p2  addr2   c2  3

2 和 3 是最常出现的响应。

Answer 1

您应该仅按您想要获取其频率的列进行分组。

SELECT response, COUNT(*) AS cr
FROM Prop
GROUP BY response
ORDER BY cr DESC
LIMIT 1

您不应在 SELECT 列表中包含其他列，因为对于具有相同响应的行，它们是不同的。

如果您想查看具有该响应的行，可以使用此子查询连接表。

SELECT p.*, c.cr
FROM Prop AS p
JOIN (
    SELECT response, COUNT(*) AS cr
    FROM Prop
    GROUP BY response
    ORDER BY cr DESC
    LIMIT 1
) AS c ON p.response = c.response