如果可以将ID作为逗号分隔的列表处理，则可以使用：

select cnt, group_concat(id)
from (select id, count(*) as cnt
      from t1
      group by id
     ) i
order by cnt
limit 1;

在MySQL5.x中，我会引用一个子查询来获取您想要过滤的最大值。。。

select id, count(*) c
from t1
group by id
having c = (SELECT MAX(c) FROM (SELECT COUNT(*) c FROM t1 GROUP BY id) t1_agg)

或者。。。

select id, count(*) c
from t1
group by id
having c = (
  SELECT COUNT(*)
    FROM t1
GROUP BY id
ORDER BY COUNT(*) DESC
   LIMIT 1
)

在mysql 8中，我将使用一个窗口函数。。。

WITH
  t1_agg AS
(
  SELECT
    id,
    COUNT(*)   AS c,
    MAX(COUNT(*)) OVER ()   AS max_c
  FROM
    t1
  GROUP BY
    id
)
SELECT
  *
FROM
  t1_agg
WHERE
  c = max_c

您可以使用子查询，只需选择 id 符合 max(id) ，就像。。。

SELECT FirstName, Count(id) AS count
FROM Person
GROUP BY FirstName
HAVING count = (
    SELECT MAX(count1)
    FROM (
        SELECT FirstName, Count(id) AS count1
        FROM Person
        GROUP BY FirstName
    )
p2)

子查询是一个强大的工具，因为它是。。。
…另一条语句中的select语句(来源：dev.mysql.com。）