数据仓库笔试题-pdd
题目：商品活动表 goods_activity，字段id主键、goods_id 商品id,act_id 活动id,create_time 活动创建时间 、status 上线状态
2 上线 ，3 下线
问题一、每个活动的每个商品 的开始时间和结束时间？
问题二、假设数据中有脏数据，同一个活动可能 两次上线，也可能两次结束，需要把活动上线重复的状态按照时间取第一条，结束上线状态重复的按时间取最后一条。
-- 第一题：
-- id,goods_id,act_id,create_time
-- asdf345,123,bybt123,2020-05-01,2
-- asdf346,123,bybt123,2020-05-10,3
-- asdf347,123,bybt123,2020-06-15,2
-- asdf348,123,bybt123,2020-06-20,3
-- ->
-- goods_id,act_id,online_dt,offline_dt
-- 123,bybt123,2020-05-01,2020-05-10
-- 123,bybt123,2020-06-15,2020-06-20
select
goods_id,act_id,online_dt,offline_dt
from
(
select goods_id,act_id,create_time as online_dt
,lead(create_time,1,'9999-12-31') over(partition by goods_id,act_id order by create_time) as offline_dt
,status
from goods_activity
) a
where status=2
-- 第二题：
-- id,goods_id,act_id,create_time lag lead
-- asdf341,123,bybt123,2020-05-01,2 0 2
-- asdf343,123,bybt123,2020-05-02,2 2 3
-- asdf34q,123,bybt123,2020-05-10,3 2 2
-- asdf346,123,bybt123,2020-06-15,2 3 3
-- asdf348,123,bybt123,2020-06-20,3 2 3
-- asdf350,123,bybt123,2020-06-21,3 3 0
-- ->
-- goods_id,act_id,online_dt,offline_dt
-- 123,bybt123,2020-05-01,2020-05-10
-- 123,bybt123,2020-06-15,2020-06-21
select
goods_id,act_id,online_dt,offline_dt
from
(
select goods_id,act_id,create_time as online_dt
,lead(create_time,1,'9999-12-31') over(partition by goods_id,act_id order by create_time) as offline_dt
,status
from
(
select
goods_id,act_id,create_time,status,last_status,lag_status
from
(
select
goods_id,act_id,create_time,status,
lead(status,1,0) over(partition by goods_id,act_id order by create_time) as last_status,
-- row_number() over(partition by goods_id,act_id,status order by create_time) as
lag(status,1,0) over(partition by goods_id,act_id order by create_time) as lag_status
from (
select 'asdf341' as id ,123 as goods_id,'bybt123' as act_id, '2020-05-01' as create_time, 2 as status UNiOn all
select 'asdf343' as id ,123 as goods_id,'bybt123' as act_id, '2020-05-02' as create_time, 2 as status UNiOn all
select 'asdf34q' as id ,123 as goods_id,'bybt123' as act_id, '2020-05-10' as create_time, 3 as status UNiOn all
select 'asdf346' as id ,123 as goods_id,'bybt123' as act_id, '2020-06-15' as create_time, 2 as status UNiOn all
select 'asdf348' as id ,123 as goods_id,'bybt123' as act_id, '2020-06-20' as create_time, 3 as status UNiOn all
select 'asdf350' as id ,123 as goods_id,'bybt123' as act_id, '2020-06-21' as create_time, 3 as status
)goods_activity
) a
where case when status=2 and status-lag_status <>0 then true
when status=3 and status-last_status <>0 then true end
) a
) a
where status=2