题目描述
x城市建立了一个新的stadium,并有下面名为stadium的表。写出一个查询语言找出人数连续三天及三天以上大于100的顾客信息。
stadium表
输出结果题目解答
连续给表起三次别名,再利用where语句选择题目要求的条件即可。
select distinct t1.*
from stadium t1, stadium t2, stadium t3
where t1.people >= 100 and t2.people >= 100 and t3.people >= 100
and
(
(t1.id - t2.id = 1 and t1.id - t3.id = 2 and t2.id - t3.id =1) #t1, t2, t3
or
(t2.id - t1.id = 1 and t2.id - t3.id = 2 and t1.id - t3.id =1) #t2, t1, t3
or
(t3.id - t2.id = 1 and t2.id - t1.id =1 and t3.id - t1.id = 2) #t3, t2, t1
)
order by t1.id
;