题解 | #话题的分布情况#
话题的分布情况
https://www.nowcoder.com/practice/3f0d5c83b48b450888921b6189be288f
select substring_index(subject_set,',',1) subject_id1, count(id) cnt from comment_detail where substring_index(substring_index(subject_set,',',2),',',-1) = 1002 group by subject_id1 order by subject_id1