数据准备：
cookie1,2015-04-10,1
cookie1,2015-04-11,5
cookie1,2015-04-12,7
cookie1,2015-04-13,3
cookie1,2015-04-14,2
cookie1,2015-04-15,4
cookie1,2015-04-16,4
建表语句：
create database if not exists myhive;
use myhive;
drop table if exists cookie;
create table cookie(cookieid string, createtime string, pv int) row format delimited fields terminated by ',';
load data local inpath "/home/hadoop/cookie.txt" into table cookie;
select * from cookie;
desc cookie;
1.SQL语句： SUM
SELECT cookieid,createtime,pv,
SUM(pv) OVER (PARTITION BY cookieid ORDER BY createtime) AS pv1, -- 默认为从起点到当前行
SUM(pv) OVER(PARTITION BY cookieid ORDER BY createtime ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS pv2, --从起点到当前行，结果同pv1
SUM(pv) OVER(PARTITION BY cookieid) AS pv3, --分组内所有行
SUM(pv) OVER(PARTITION BY cookieid ORDER BY createtime ROWS BETWEEN 3 PRECEDING AND CURRENT ROW) AS pv4, --当前行+往前3行
SUM(pv) OVER(PARTITION BY cookieid ORDER BY createtime ROWS BETWEEN 3 PRECEDING AND 1 FOLLOWING) AS pv5, --当前行+往前3行+往后1行
SUM(pv) OVER(PARTITION BY cookieid ORDER BY createtime ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) AS pv6 --当前行+往后所有行
FROM cookie;
结果：
cookieid createtime pv pv1 pv2 pv3 pv4 pv5 pv6
cookie1 2015-04-16 4 26 26 26 13 13 4
cookie1 2015-04-15 4 22 22 26 16 20 8
cookie1 2015-04-14 2 18 18 26 17 21 10
cookie1 2015-04-13 3 16 16 26 16 18 13
cookie1 2015-04-12 7 13 13 26 13 16 20
cookie1 2015-04-11 5 6 6 26 6 13 25
cookie1 2015-04-10 1 1 1 26 1 6 26
注解：
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
pv2: 同pv1
pv3: 分组内(cookie1)所有的pv累加
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
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
pv6: 分组内当前行+往后所有行，如，13号=13号+14号+15号+16号=3+2+4+4=13，14号=14号+15号+16号=2+4+4=10
如果不指定ROWS BETWEEN,默认为从起点到当前行;
如果不指定ORDER BY，则将分组内所有值累加;
关键是理解ROWS BETWEEN含义,也叫做WINDOW子句：
PRECEDING：往前
FOLLOWING：往后
CURRENT ROW：当前行
UNBOUNDED：起点，UNBOUNDED PRECEDING 表示从前面的起点， UNBOUNDED FOLLOWING：表示到后面的终点
–其他AVG，MIN，MAX，和SUM用法一样。
2.SQL语句： AVG
SELECT cookieid,createtime,pv,
AVG(pv) OVER(PARTITION BY cookieid ORDER BY createtime) AS pv1, -- 默认为从起点到当前行
AVG(pv) OVER(PARTITION BY cookieid ORDER BY createtime ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS pv2, --从起点到当前行，结果同pv1
AVG(pv) OVER(PARTITION BY cookieid) AS pv3, --分组内所有行
AVG(pv) OVER(PARTITION BY cookieid ORDER BY createtime ROWS BETWEEN 3 PRECEDING AND CURRENT ROW) AS pv4, --当前行+往前3行
AVG(pv) OVER(PARTITION BY cookieid ORDER BY createtime ROWS BETWEEN 3 PRECEDING AND 1 FOLLOWING) AS pv5, --当前行+往前3行+往后1行
AVG(pv) OVER(PARTITION BY cookieid ORDER BY createtime ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) AS pv6 --当前行+往后所有行
FROM cookie;
结果：
cookie1 2015-04-16 4 3.7142857142857144 3.7142857142857144 3.7142857142857144 3.25 3.25 4.0
cookie1 2015-04-15 4 3.6666666666666665 3.6666666666666665 3.7142857142857144 4.0 4.0 4.0
cookie1 2015-04-14 2 3.6 3.6 3.7142857142857144 4.25 4.2 3.3333333333333335
cookie1 2015-04-13 3 4.0 4.0 3.7142857142857144 4.0 3.6 3.25
cookie1 2015-04-12 7 4.333333333333333 4.333333333333333 3.7142857142857144 4.333333333333333 4.0 4.0
cookie1 2015-04-11 5 3.0 3.0 3.7142857142857144 3.0 4.333333333333333 4.166666666666667
cookie1 2015-04-10 1 1.0 1.0 3.7142857142857144 1.0 3.0 3.7142857142857144
3.SQL语句： MIN
SELECT cookieid, createtime, pv,
MIN(pv) OVER(PARTITION BY cookieid ORDER BY createtime) AS pv1, -- 默认为从起点到当前行
MIN(pv) OVER(PARTITION BY cookieid ORDER BY createtime ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS pv2, --从起点到当前行，结果同pv1
MIN(pv) OVER(PARTITION BY cookieid) AS pv3, --分组内所有行
MIN(pv) OVER(PARTITION BY cookieid ORDER BY createtime ROWS BETWEEN 3 PRECEDING AND CURRENT ROW) AS pv4, --当前行+往前3行
MIN(pv) OVER(PARTITION BY cookieid ORDER BY createtime ROWS BETWEEN 3 PRECEDING AND 1 FOLLOWING) AS pv5, --当前行+往前3行+往后1行
MIN(pv) OVER(PARTITION BY cookieid ORDER BY createtime ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) AS pv6 --当前行+往后所有行
FROM cookie;
结果：
cookie1 2015-04-16 4 1 1 1 2 2 4
cookie1 2015-04-15 4 1 1 1 2 2 4
cookie1 2015-04-14 2 1 1 1 2 2 2
cookie1 2015-04-13 3 1 1 1 1 1 2
cookie1 2015-04-12 7 1 1 1 1 1 2
cookie1 2015-04-11 5 1 1 1 1 1 2
cookie1 2015-04-10 1 1 1 1 1 1 1
4.SQL语句： MAX
SELECT cookieid,createtime,pv,
MAX(pv) OVER(PARTITION BY cookieid ORDER BY createtime) AS pv1, -- 默认为从起点到当前行
MAX(pv) OVER(PARTITION BY cookieid ORDER BY createtime ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS pv2, --从起点到当前行，结果同pv1
MAX(pv) OVER(PARTITION BY cookieid) AS pv3, --分组内所有行
MAX(pv) OVER(PARTITION BY cookieid ORDER BY createtime ROWS BETWEEN 3 PRECEDING AND CURRENT ROW) AS pv4, --当前行+往前3行
MAX(pv) OVER(PARTITION BY cookieid ORDER BY createtime ROWS BETWEEN 3 PRECEDING AND 1 FOLLOWING) AS pv5, --当前行+往前3行+往后1行
MAX(pv) OVER(PARTITION BY cookieid ORDER BY createtime ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) AS pv6 ---当前行+往后所有行
FROM cookie;
结果：
cookie1 2015-04-16 4 7 7 7 4 4 4
cookie1 2015-04-15 4 7 7 7 7 7 4
cookie1 2015-04-14 2 7 7 7 7 7 4
cookie1 2015-04-13 3 7 7 7 7 7 4
cookie1 2015-04-12 7 7 7 7 7 7 7
cookie1 2015-04-11 5 5 5 7 5 7 7
cookie1 2015-04-10 1 1 1 7 1 5 7
