2.11 Hive中数据导入导出Import和Export使用

https://cwiki.apache.org/confluence/display/Hive/LanguageManual+ImportExport

一、Export、Import

Export
    导出，将Hive表中的数据，导出到外部

Import
    导入，将外部数据导入Hive表中

二、Export

1、语法

EXPORT TABLE tablename TO 'export_target_path';

2、用法

#把emp表导出到hdfs上
hive (default)> EXPORT TABLE default.emp TO '/user/root/hive/export/emp_exp';

hive (default)> dfs -ls -R /user/root/hive/export;
drwxr-xr-x   - root supergroup          0 2019-04-24 10:06 /user/root/hive/export/emp_exp
-rw-r--r--   1 root supergroup       1588 2019-04-24 10:06 /user/root/hive/export/emp_exp/_metadata
drwxr-xr-x   - root supergroup          0 2019-04-24 10:06 /user/root/hive/export/emp_exp/data
-rw-r--r--   1 root supergroup        659 2019-04-24 10:06 /user/root/hive/export/emp_exp/data/emp.txt

三、Import

1、语法

IMPORT TABLE tablename FROM 'source_path';

2、用法

#先在db_hive库下创建一个emp表
hive (default)> use db_hive;
OK
Time taken: 0.012 seconds

hive (db_hive)> show tables;
OK
tab_name
student
Time taken: 0.014 seconds, Fetched: 1 row(s)

hive (db_hive)> create table db_hive.emp like default.emp;
OK
Time taken: 0.087 seconds

hive (db_hive)> show tables;                              
OK
tab_name
emp
student
Time taken: 0.011 seconds, Fetched: 2 row(s)



#导入
hive (db_hive)> import table db_hive.emp from '/user/root/hive/export/emp_exp';

hive (db_hive)> select * from db_hive.emp;
OK
emp.empno    emp.ename    emp.job    emp.mgr    emp.hiredate    emp.sal    emp.comm    emp.deptno
7369    SMITH    CLERK    7902    1980-12-17    800.0    NULL    20
7499    ALLEN    SALESMAN    7698    1981-2-20    1600.0    300.0    30
7521    WARD    SALESMAN    7698    1981-2-22    1250.0    500.0    30
7566    JONES    MANAGER    7839    1981-4-2    2975.0    NULL    20
7654    MARTIN    SALESMAN    7698    1981-9-28    1250.0    1400.0    30
7698    BLAKE    MANAGER    7839    1981-5-1    2850.0    NULL    30
7782    CLARK    MANAGER    7839    1981-6-9    2450.0    NULL    10
7788    SCOTT    ANALYST    7566    1987-4-19    3000.0    NULL    20
7839    KING    PRESIDENT    NULL    1981-11-17    5000.0    NULL    10
7844    TURNER    SALESMAN    7698    1981-9-8    1500.0    0.0    30
7876    ADAMS    CLERK    7788    1987-5-23    1100.0    NULL    20
7900    JAMES    CLERK    7698    1981-12-3    950.0    NULL    30
7902    FORD    ANALYST    7566    1981-12-3    3000.0    NULL    20
7934    MILLER    CLERK    7782    1982-1-23    1300.0    NULL    10
Time taken: 0.029 seconds, Fetched: 14 row(s)


hive (db_hive)> dfs -ls -R /user/hive/warehouse/db_hive.db/emp;                
-rw-r--r--   1 root supergroup        659 2019-04-24 10:15 /user/hive/warehouse/db_hive.db/emp/emp.txt

四、Export、Import的其他高级用法

Export、Import还可以用在外部表、分区表上面等，这个可以等用到的时候再看；