Hive中提供了越来越多的分析函数，用于完成负责的统计分析。抽时间将所有的分析窗口函数理一遍，将陆续发布。
今天先看几个基础的，SUM、AVG、MIN、MAX。
用于实现分组内所有和连续累积的统计。
Hive版本为 apache-hive-0.13.1
数据准备：
CREATE EXTERNAL TABLE lxw1234 (
cookieid string,
createtime string, --day
pv INT
) ROW FORMAT DELIMITED
FIELDS TERMINATED BY ','
stored as textfile location '/tmp/lxw11/';
DESC lxw1234;
cookieid STRING
createtime STRING
pv INT
hive> select * from lxw1234;
OK
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
SUM：
注意,结果和ORDER BY相关,默认为升序
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 lxw1234; cookieid createtime pv pv1 pv2 pv3 pv4 pv5 pv6 ----------------------------------------------------------------------------- cookie1 2015-04-10 1 1 1 26 1 6 26 cookie1 2015-04-11 5 6 6 26 6 13 25 cookie1 2015-04-12 7 13 13 26 13 16 20 cookie1 2015-04-13 3 16 16 26 16 18 13 cookie1 2015-04-14 2 18 18 26 17 21 10 cookie1 2015-04-15 4 22 22 26 16 20 8 cookie1 2015-04-16 4 26 26 26 13 13 4 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 （WINDOW子句）含义：
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。
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 lxw1234; cookieid createtime pv pv1 pv2 pv3 pv4 pv5 pv6 ----------------------------------------------------------------------------- cookie1 2015-04-10 1 1.0 1.0 3.7142857142857144 1.0 3.0 3.7142857142857144 cookie1 2015-04-11 5 3.0 3.0 3.7142857142857144 3.0 4.333333333333333 4.166666666666667 cookie1 2015-04-12 7 4.333333333333333 4.333333333333333 3.7142857142857144 4.333333333333333 4.0 4.0 cookie1 2015-04-13 3 4.0 4.0 3.7142857142857144 4.0 3.6 3.25 cookie1 2015-04-14 2 3.6 3.6 3.7142857142857144 4.25 4.2 3.3333333333333335 cookie1 2015-04-15 4 3.6666666666666665 3.6666666666666665 3.7142857142857144 4.0 4.0 4.0 cookie1 2015-04-16 4 3.7142857142857144 3.7142857142857144 3.7142857142857144 3.25 3.25 4.0
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 lxw1234; cookieid createtime pv pv1 pv2 pv3 pv4 pv5 pv6 ----------------------------------------------------------------------------- cookie1 2015-04-10 1 1 1 1 1 1 1 cookie1 2015-04-11 5 1 1 1 1 1 2 cookie1 2015-04-12 7 1 1 1 1 1 2 cookie1 2015-04-13 3 1 1 1 1 1 2 cookie1 2015-04-14 2 1 1 1 2 2 2 cookie1 2015-04-15 4 1 1 1 2 2 4 cookie1 2015-04-16 4 1 1 1 2 2 4
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 lxw1234; cookieid createtime pv pv1 pv2 pv3 pv4 pv5 pv6 ----------------------------------------------------------------------------- cookie1 2015-04-10 1 1 1 7 1 5 7 cookie1 2015-04-11 5 5 5 7 5 7 7 cookie1 2015-04-12 7 7 7 7 7 7 7 cookie1 2015-04-13 3 7 7 7 7 7 4 cookie1 2015-04-14 2 7 7 7 7 7 4 cookie1 2015-04-15 4 7 7 7 7 7 4 cookie1 2015-04-16 4 7 7 7 4 4 4
转自： http://lxw1234.com/archives/tag/hive-window-functions
更多的分析函数，如：NTILE,ROW_NUMBER,RANK,DENSE_RANK
CUME_DIST,PERCENT_RANK
LAG,LEAD,FIRST_VALUE,LAST_VALUE
GROUPING SETS,GROUPING__ID,CUBE,ROLLUP