Question

我有一个名为food的表：

CREATE TABLE food(
name varchar(30) primary key,
type varchar(30)
);

我想找到此表中出现次数最多的type。

我可以使用

找到它

SELECT type
FROM food
GROUP BY type
ORDER BY count(type) DESC
LIMIT 1

但limit 1未包含在标准中。如何使用MAX找到相同的结果？例如，我想要像

这样的东西

SELECT type
FROM food
GROUP BY type
HAVING count(type) = MAX(count(type));

HAVING count(type) = MAX(count(type));是不允许的。

Answer 1

可能效率不高

SELECT type
FROM food
GROUP BY type
HAVING COUNT(type) =
(
    SELECT MAX(counting) FROM
    (
        SELECT COUNT(type) AS counting
        FROM food
        GROUP BY type
    ) t
)

Answer 2

使用cte（公用表格表达式），GROUP BY与COUNT一起使用：

with cte as
(
    SELECT type, count(*) as cnt
    FROM food
    GROUP BY type
)
select type from cte
where cnt = (select max(cnt) from cte)

如果有平局，将返回两行。

（我不知道与Madhivanan的回答相比，这是否会有相同或更好的表现。无论如何都要少打字。）

使用max查找最常见的collumn_name

2 个答案: