Hive分析窗口函数(一) SUM,AVG,MIN,MAX

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。
<p>用于实现分组内所有和连续累积的统计。</p>

CREATE EXTERNAL TABLE yeshuai_test(    cookieid string,    createtime string, --day    pv INT    ) ROW FORMAT DELIMITED    FIELDS TERMINATED BY ','

为了测试方便，不用到hadoop上去上传文件进行测试

直接进入本地的一个文件夹进行编辑数据导入，这里我的文件夹路径为/home/work/yeshuai/data1.txt

用vim 编辑，复制进去数据

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

然后 hive>select * from yeshuai_test 进行测试，有数据的话，测试环境准备ok了

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 yeshuai_test;

    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。

<div class="blockcode"><div id="code_cxN"><ol><li>  --AVG
</li><li>    SELECT cookieid,
</li><li>    createtime,
</li><li>    pv,
</li><li>    AVG(pv) OVER(PARTITION BY cookieid ORDER BY createtime) AS pv1, -- 默认为从起点到当前行
</li><li>    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
</li><li>    AVG(pv) OVER(PARTITION BY cookieid) AS pv3,        --分组内所有行
</li><li>    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
</li><li>    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
</li><li>    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
</li><li>    FROM lxw1234;
</li><li>    cookieid createtime pv pv1 pv2 pv3 pv4 pv5 pv6
</li><li>    -----------------------------------------------------------------------------
</li><li>    cookie1 2015-04-10 1 1.0 1.0 3.7142857142857144 1.0 3.0 3.7142857142857144
</li><li>    cookie1 2015-04-11 5 3.0 3.0 3.7142857142857144 3.0 4.333333333333333 4.166666666666667
</li><li>    cookie1 2015-04-12 7 4.333333333333333 4.333333333333333 3.7142857142857144 4.333333333333333 4.0 4.0
</li><li>    cookie1 2015-04-13 3 4.0 4.0 3.7142857142857144 4.0 3.6 3.25
</li><li>    cookie1 2015-04-14 2 3.6 3.6 3.7142857142857144 4.25 4.2 3.3333333333333335
</li><li>    cookie1 2015-04-15 4 3.6666666666666665 3.6666666666666665 3.7142857142857144 4.0 4.0 4.0
</li><li>    cookie1 2015-04-16 4 3.7142857142857144 3.7142857142857144 3.7142857142857144 3.25 3.25 4.0</li></ol></div>
</div><div class="blockcode"><div id="code_L6F"><ol><li>    --MIN
</li><li>    SELECT cookieid,
</li><li>    createtime,
</li><li>    pv,
</li><li>    MIN(pv) OVER(PARTITION BY cookieid ORDER BY createtime) AS pv1, -- 默认为从起点到当前行
</li><li>    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
</li><li>    MIN(pv) OVER(PARTITION BY cookieid) AS pv3,        --分组内所有行
</li><li>    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
</li><li>    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
</li><li>    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
</li><li>    FROM lxw1234;
</li><li>     
</li><li>    cookieid createtime pv pv1 pv2 pv3 pv4 pv5 pv6
</li><li>    -----------------------------------------------------------------------------
</li><li>    cookie1 2015-04-10 1 1 1 1 1 1 1
</li><li>    cookie1 2015-04-11 5 1 1 1 1 1 2
</li><li>    cookie1 2015-04-12 7 1 1 1 1 1 2
</li><li>    cookie1 2015-04-13 3 1 1 1 1 1 2
</li><li>    cookie1 2015-04-14 2 1 1 1 2 2 2
</li><li>    cookie1 2015-04-15 4 1 1 1 2 2 4
</li><li>    cookie1 2015-04-16 4 1 1 1 2 2 4</li></ol></div>
</div><div class="blockcode"><div id="code_f2D"><ol><li>    ----MAX
</li><li>    SELECT cookieid,
</li><li>    createtime,
</li><li>    pv,
</li><li>    MAX(pv) OVER(PARTITION BY cookieid ORDER BY createtime) AS pv1, -- 默认为从起点到当前行
</li><li>    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
</li><li>    MAX(pv) OVER(PARTITION BY cookieid) AS pv3,        --分组内所有行
</li><li>    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
</li><li>    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
</li><li>    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
</li><li>    FROM lxw1234;
</li><li>     
</li><li>    cookieid createtime pv pv1 pv2 pv3 pv4 pv5 pv6
</li><li>    -----------------------------------------------------------------------------
</li><li>    cookie1 2015-04-10 1 1 1 7 1 5 7
</li><li>    cookie1 2015-04-11 5 5 5 7 5 7 7
</li><li>    cookie1 2015-04-12 7 7 7 7 7 7 7
</li><li>    cookie1 2015-04-13 3 7 7 7 7 7 4
</li><li>    cookie1 2015-04-14 2 7 7 7 7 7 4
</li><li>    cookie1 2015-04-15 4 7 7 7 7 7 4
</li><li>    cookie1 2015-04-16 4 7 7 7 4 4 4</li></ol></div></div>

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Hive分析窗口函数(一) SUM,AVG,MIN,MAX

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