最简单的思路为三表连接，连接关系则为日期或id之间的关系。
select distinct s1.* from stadium s1, stadium s2, stadium s3
where ((s1.id = s2.id - 1 and s1.id = s3.id - 2)
or (s1.id = s2.id - 1 and s1.id = s3.id + 1)
or (s1.id = s2.id + 1 and s1.id = s3.id + 2))
and (s1.people >= 100 and s2.people >= 100 and s3.people >= 100)
order by id asc
