Hive基本操作

在hive命令终端直接导入文本数据：

hive> LOAD DATA LOCAL INPATH '/home/simon/hive_test/a.txt' OVERWRITE INTO TABLE w_a;

 查看特征：

hive> select A.usrid, A.age, B.time from w_a A join w_b B on A.usrid = B.usrid; 

通过LOAD命令直接将hadoop文件系统上的文件导入，不加LOCAL

hive> LOAD DATA INPATH '/user_name.data.utf.txt' OVERWRITE INTO TABLE u_info;

 hive数据导入另外一种方法：

hive> insert into table w_d select usrid, age from w_a limit 2;

 从Hive导出数据到local本地

hive> insert overwrite local directory '/home/badou/hive_test/data/1.txt' select usrid, age from w_a;

从Hive导出数据到HDFS上

hive> insert overwrite directory '/hive_data' select usrid, age from w_a;

利用partition导入，查询数据

hive> load data local inpath '/home/badou/hive_test/p1.txt' into table p_t_2;                       
Copying data from file:/home/badou/hive_test/p1.txt
Copying file: file:/home/badou/hive_test/p1.txt
Loading data to table default.p_t_2
Table default.p_t_2 stats: [numFiles=1, numRows=0, totalSize=72, rawDataSize=0]
OK
Time taken: 0.41 seconds
hive> select * from p_t_2;
OK
user2   28      20170302
user4   30      20170302
user6   32      20170302
user8   34      20170302
Time taken: 0.081 seconds, Fetched: 4 row(s)
hive> select * from p_t_2 where dt='20170302';                               
Total jobs = 1
Launching Job 1 out of 1
Number of reduce tasks is set to 0 since there's no reduce operator
Starting Job = job_201908120758_0009, Tracking URL = http://master:50030/jobdetails.jsp?jobid=job_201908120758_0009
Kill Command = /usr/local/src/hadoop-1.2.1/libexec/../bin/hadoop job  -kill job_201908120758_0009
Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 0
2019-08-14 20:36:11,750 Stage-1 map = 0%,  reduce = 0%
2019-08-14 20:36:20,899 Stage-1 map = 100%,  reduce = 0%, Cumulative CPU 2.98 sec
2019-08-14 20:36:26,020 Stage-1 map = 100%,  reduce = 100%, Cumulative CPU 2.98 sec
MapReduce Total cumulative CPU time: 2 seconds 980 msec
Ended Job = job_201908120758_0009
MapReduce Jobs Launched: 
Job 0: Map: 1   Cumulative CPU: 2.98 sec   HDFS Read: 283 HDFS Write: 72 SUCCESS
Total MapReduce CPU Time Spent: 2 seconds 980 msec
OK
user2   28      20170302
user4   30      20170302
user6   32      20170302
user8   34      20170302
Time taken: 21.554 seconds, Fetched: 4 row(s)
hive> 

创建UDF函数：

hive> create temporary function uppercase as 'com.badou.hive.udf.Uppercase';
OK
Time taken: 0.097 seconds