题解 | #大小写混乱时的筛选统计#
大小写混乱时的筛选统计
https://www.nowcoder.com/practice/81cb12931a604811ae69d332515c7734
select
e.tag,
count(c.id)
from
exam_record c,
examination_info d,
(
select
b.tag
from
exam_record a,
examination_info b
where
a.exam_id=b.exam_id
group by b.tag
having count(b.id)<3
) e
where
c.exam_id=d.exam_id
and d.tag = upper(e.tag)
and d.tag<>e.tag
group by e.tag
order by count(id) desc
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