在没有 ORDER BY SQL MariaDB 的列中查找频率最低的值

Finding the least frequest value in a column WITHOUT ORDER BY SQL MariaDB

sql
mariadb

我有一个级别的注册学生架构，问题是我必须找到哪个级别的学生人数最少，这些学生属于“2000/01”年并且课程 ID 为 'G500' 但是，我无法使用 ORDER BY 或 LIMIT。这是我能想到的最佳答案。

SELECT lvl
FROM   enrl
WHERE  ayr = '2000/01'
       AND pid = 'G500'
GROUP  BY lvl
ORDER  BY Count(*) DESC;

WITH cte AS (
    SELECT lvl, COUNT(*) as count
    FROM   enrl
    WHERE  ayr = '2000/01'
           AND pid = 'G500'
    GROUP  BY lvl
)
SELECT t1.lvl FROM cte AS t1
LEFT OUTER JOIN cte AS t2 ON t1.count < t2.count
WHERE t2.count IS NULL;