Hive SQL 分类

题目：

请使用Hive SQL实现下面的题目。

下面是一张表名为user_buy_log的表，有三个字段，user(用户)，grp(分组编号)，time（购物时间）。

需要将用户按照grp分组，对time进行升序排序，

如果用户间购物时间间隔小于5分钟，则认为是一个小团体，标号为1；

如果时间间隔大于5分，标号开始累加1。

user	grp	time
num15	B	2019-01-06 13:44:20.0
num17	B	2019-01-06 13:47:24.0
num10	A	2019-01-09 15:45:50.0
num18	B	2019-01-06 13:47:49.0
num16	B	2019-01-06 13:46:40.0
num3	A	2019-01-09 11:21:12.0
num4	A	2019-01-09 11:24:42.0
num1	A	2019-01-09 09:16:08.0
num12	B	2019-01-06 13:43:32.0
num13	B	2019-01-06 13:43:44.0
num2	A	2019-01-09 09:17:11.0
num7	A	2019-01-09 15:42:28.0
num11	A	2019-01-09 15:46:05.0
num5	A	2019-01-09 11:24:53.0
num9	A	2019-01-09 15:45:32.0
num8	A	2019-01-09 15:43:02.0
num6	A	2019-01-09 11:25:04.0
num14	B	2019-01-06 13:44:06.0

最终输出结果表名：user_buy_log_res，结果如下：

　　　　

结果解析：

由于num1，num2时间间隔小于5分钟，而且他们是组A的最开始的分组，因此组号（res_grp）为1。

由于num3与num2的时间间隔超过5分钟，因此num3的组号（res_grp）开始累加，因此（res_grp）为2。

Num7跟num6的间隔超过5分钟，num7组号（res_grp）开始再次累加，因此（res_grp）为3。

num12是属于新的分组B，因此其（res_grp）重新从1开始编号，因为后续用户的购物时间间隔都小于5分钟，因此编号没有再累加。

解决办法：

set hive.support.sql11.reserved.keywords=false;

create database tab

use tab

create table user_buy_log (user string, grp string,time string)
ROW FORMAT DELIMITED
FIELDS TERMINATED BY '\t'
STORED AS TEXTFILE;

load data local inpath '/home/hadoop/Desktop/user_buy_log.txt' into table user_buy_log;

CREATE TABLE user_buy_log_1 AS
SELECT user,grp,time,
CAST(( UNIX_TIMESTAMP(time)-UNIX_TIMESTAMP(lag(time) over(PARTITION BY grp ORDER BY time ASC)))/60 AS INT) period,
row_number() over (PARTITION BY grp ORDER BY time ASC) AS row_num
FROM user_buy_log;

SELECT * FROM user_buy_log_1;

CREATE TABLE user_buy_log_2 AS
SELECT user,grp,time, period , row_num,CASE
WHEN period > 5 THEN 2
WHEN period is null THEN 1
ELSE NULL
END
AS res_grp
FROM user_buy_log_1;

SELECT * FROM user_buy_log_2;

CREATE TABLE user_buy_log_3 AS
SELECT user,grp,time,row_number() over (PARTITION BY grp ORDER BY time ASC) AS row_num
FROM user_buy_log_2
WHERE res_grp is not null;

SELECT * FROM user_buy_log_3;

CREATE TABLE user_buy_log_4 AS
SELECT t2.user,t2.grp,t2.time,t2.row_num,t3.row_num AS res_grp
FROM user_buy_log_2 t2
LEFT JOIN user_buy_log_3 t3
ON t2.user = t3.user;

SELECT * FROM user_buy_log_4;

CREATE TABLE user_buy_log_res AS
SELECT user,grp,time,
MAX(res_grp) over(PARTITION BY grp ORDER BY time ASC) AS res_grp
FROM user_buy_log_4;

SELECT * FROM user_buy_log_res;

所有代码：

set hive.support.sql11.reserved.keywords=false;

create database tab

use tab

create table user_buy_log (user string, grp string,time string)
ROW FORMAT DELIMITED
FIELDS TERMINATED BY '\t'
STORED AS TEXTFILE;

load data local inpath '/home/hadoop/Desktop/user_buy_log.txt' into table user_buy_log; 

CREATE TABLE user_buy_log_1 AS
SELECT user,grp,time,
CAST(( UNIX_TIMESTAMP(time)-UNIX_TIMESTAMP(lag(time) over(PARTITION BY grp ORDER BY time ASC)))/60 AS INT)  period,
row_number() over (PARTITION BY grp ORDER BY time ASC) AS row_num
FROM user_buy_log;

SELECT * FROM user_buy_log_1;

CREATE TABLE user_buy_log_2 AS
SELECT user,grp,time, period , row_num,CASE
WHEN period > 5 THEN 2
WHEN period is null THEN 1
ELSE NULL
END
AS res_grp
FROM user_buy_log_1;

SELECT * FROM user_buy_log_2;

CREATE TABLE user_buy_log_3 AS
SELECT user,grp,time,row_number() over (PARTITION BY grp ORDER BY time ASC) AS row_num
FROM user_buy_log_2
WHERE res_grp is not null;

SELECT * FROM user_buy_log_3;

CREATE TABLE user_buy_log_4 AS
SELECT t2.user,t2.grp,t2.time,t2.row_num,t3.row_num AS res_grp
FROM user_buy_log_2 t2
LEFT JOIN user_buy_log_3 t3
ON t2.user = t3.user;

SELECT * FROM user_buy_log_4;

CREATE TABLE user_buy_log_res AS
SELECT user,grp,time,
MAX(res_grp) over(PARTITION BY grp ORDER BY time ASC) AS res_grp
FROM user_buy_log_4;

SELECT * FROM user_buy_log_res;

user_buy_log.txt

num15    B    2019-01-06 13:44:20.0
num17    B    2019-01-06 13:47:24.0
num10    A    2019-01-09 15:45:50.0
num18    B    2019-01-06 13:47:49.0
num16    B    2019-01-06 13:46:40.0
num3    A    2019-01-09 11:21:12.0
num4    A    2019-01-09 11:24:42.0
num1    A    2019-01-09 09:16:08.0
num12    B    2019-01-06 13:43:32.0
num13    B    2019-01-06 13:43:44.0
num2    A    2019-01-09 09:17:11.0
num7    A    2019-01-09 15:42:28.0
num11    A    2019-01-09 15:46:05.0
num5    A    2019-01-09 11:24:53.0
num9    A    2019-01-09 15:45:32.0
num8    A    2019-01-09 15:43:02.0
num6    A    2019-01-09 11:25:04.0
num14    B    2019-01-06 13:44:06.0