hive之窗口函數

窗口函數

1．相關函數說明

COVER()：指定分析函數工作的數據窗口大小，這個數據窗口大小可能會隨着行的變而變化

CURRENT ROW：當前行

n PRECEDING：往前n行數據

n FOLLOWING：往后n行數據

UNBOUNDED：起點，UNBOUNDED PRECEDING 表示從前面的起點， UNBOUNDED FOLLOWING表示到后面的終點

LAG(col,n)：往前第n行數據

LEAD(col,n)：往后第n行數據

 

NTILE(n)：把有序分區中的行分發到指定數據的組中，各個組有編號，編號從1開始，對於每一行，NTILE返回此行所屬的組的編號。注意：n必須為int類型。

2．數據准備：name，orderdate，cost

jack,2017-01-01,10

tony,2017-01-02,15

jack,2017-02-03,23

tony,2017-01-04,29

jack,2017-01-05,46

jack,2017-04-06,42

tony,2017-01-07,50

jack,2017-01-08,55

mart,2017-04-08,62

mart,2017-04-09,68

neil,2017-05-10,12

mart,2017-04-11,75

neil,2017-06-12,80

mart,2017-04-13,94

 

3．需求

（1）查詢在2017年4月份購買過的顧客及總人數

（2）查詢顧客的購買明細及月購買總額

（3）上述的場景,要將cost按照日期進行累加

（4）查詢顧客上次的購買時間

（5）查詢前20%時間的訂單信息

4．創建本地business.txt，導入數據

[atguigu@hadoop102 datas]$ vi business.txt

5．創建hive表並導入數據

create table business(

name string,

orderdate string,

cost int

) ROW FORMAT DELIMITED FIELDS TERMINATED BY ',';

 

load data local inpath "/opt/module/datas/business.txt" into table business;

6．按需求查詢數據

（1）查詢在2017年4月份購買過的顧客及總人數

select name,count(*) over ()

from business 

where substring(orderdate,1,7) = '2017-04'

group by name;

（2）查詢顧客的購買明細及月購買總額

select name,orderdate,cost,sum(cost) over(partition by month(orderdate)) from

 business;

（3）上述的場景,要將cost按照日期進行累加

select name,orderdate,cost,

sum(cost) over() as sample1,--所有行相加

sum(cost) over(partition by name) as sample2,--按name分組，組內數據相加

sum(cost) over(partition by name order by orderdate) as sample3,--按name分組，組內數據累加

sum(cost) over(partition by name order by orderdate rows between UNBOUNDED PRECEDING and current row ) as sample4 ,--和sample3一樣,由起點到當前行的聚合

sum(cost) over(partition by name order by orderdate rows between 1 PRECEDING and current row) as sample5, --當前行和前面一行做聚合

sum(cost) over(partition by name order by orderdate rows between 1 PRECEDING AND 1 FOLLOWING ) as sample6,--當前行和前邊一行及后面一行

sum(cost) over(partition by name order by orderdate rows between current row and UNBOUNDED FOLLOWING ) as sample7 --當前行及后面所有行

from business;

（4）查看顧客上次的購買時間

select name,orderdate,cost,

lag(orderdate,1,'1900-01-01') over(partition by name order by orderdate ) as time1, lag(orderdate,2) over (partition by name order by orderdate) as time2

from business;

（5）查詢前20%時間的訂單信息

select * from (

    select name,orderdate,cost, ntile(5) over(order by orderdate) sorted

    from business

) t

where sorted = 1;