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
with
a as (
select
tag,
count(start_time) answer_cnt
from
examination_info i,
exam_record r
where
i.exam_id = r.exam_id
group by
tag
)
select
a.tag tag,
b.answer_cnt
from
a,
a b
where
upper(a.tag) = b.tag
and a.tag != b.tag
and a.answer_cnt < 3;
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