求最大的出现一次的数字 表嵌套

# 只出现一次的最大数
num
8
8
2
2
5
5

2

7

结果是7
num
8

8
2

2
5

5
1

1

结果是null

select max(num) as num
from mynumbers
where num in (
  select num
  from mynumbers
  group by num
  having count(num)<=1)
;

posted @ 2025-04-15 19:23  胖豆芽  阅读(7)  评论(0)    收藏  举报