SQL 累计和

SQL 累计和
计算逻辑：

-- 日期
with date as (
  select distinct
   concat(substr(date,1,4),substr(date,6,2)) as year_month 
   ,trunc(date,'MM') as month_frist  -- 每个月第一天
  from AAAA.DATE -- 每天日历表
  where date between '2018-01-01' and  date_sub('${zdt.format("yyyy-MM-dd")}',1) -- 昨天的函数 
)

--- 每个月新上线的商户数
,shopnum as (select 
 concat(substr(online_time,1,4),substr(online_time,6,2)) as year_month
,count(shop) as shopnum
from  BBBB.SHOP_TABLE -- 每天上线的商户表
group by concat(substr(online_time,1,4),substr(online_time,6,2)))

-- 每个月匹上每个月新上线的商户数
,end as (select 
date.year_month ,month_frist
, coalesce(shopnum,0) as shopnum 
from date
left join shopnum
on date.year_month = shopnum.year_month
)

-- 用到sum()over() sum开窗函数
select 
 year_month
,month_frist
,sum(shopnum) over (order by  year_month rows between unbounded preceding and current row) as shopnum -- 累计商户数
,shopnum as shopnum_up -- 每个月新增商户数
from end

;

sum开窗函数使用：

----sum开窗函数
select cookieid
,createtime
,pv
,sum(pv) over (partition by cookieid order by createtime rows between unbounded preceding and current row) as pv1
--partition by 后可省略，当没有分组时
--pv1:分组内从起点到当前行的pv累积，如，11号的pv1=10号的pv+11号的pv, 12号=10号+11号+12号
--Oorder by createtime 按createtime对查询读取的记录进行排序，就是窗口范围内的排序
--rows between unbounded preceding and current row 定义起点和终点，
--unbounded preceding 为起点，表明从第一行开始, current row为默认值，就是这一句等价于：
--rows unbounded preceding
--preceding：在前 N 行的意思。
--FOLLOWING：在后 N 行的意思。
,sum(pv) over (partition by cookieid order by createtime) as pv2
--pv2同pv1
,sum(pv) over (partition by cookieid) as pv3
--pv3: 分组内(cookie1)所有的pv累加
,sum(pv) over (partition by cookieid order by createtime rows between 3 preceding and current row) as pv4
--pv4: 分组内当前行+往前3行，如，11号=10号+11号， 12号=10号+11号+12号， 13号=10号+11号+12号+13号， 14号=11号+12号+13号+14号
,sum(pv) over (partition by cookieid order by createtime rows between 3 preceding and 1 following) as pv5
--pv5: 分组内当前行+往前3行+往后1行，如，14号=11号+12号+13号+14号+15号=5+7+3+2+4=21
,sum(pv) over (partition by cookieid order by createtime rows between current row and unbounded following) as pv6
from CCCC.test06