Hive DML 数据操作

布满荆棘的人生 2022-02-01 11:45 301阅读 0赞

## 数据导入 ##

### 向表中装载数据（Load） ###

#### 语法 ####

load data [local] inpath '/opt/module/datas/student.txt' 
    overwrite | into table student [partition (partcol1=val1,…)]

<table> 
 <thead> 
  <tr> 
   <th>参数</th> 
   <th>说明</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>load data</td> 
   <td>加载数据</td> 
  </tr> 
  <tr> 
   <td>local</td> 
   <td>从本地加载数据到hive表；否则从HDFS加载数据到hive表</td> 
  </tr> 
  <tr> 
   <td>inpath</td> 
   <td>表示加载数据的路径</td> 
  </tr> 
  <tr> 
   <td>overwriter</td> 
   <td>表示覆盖表中的已有数据，否则表示追加</td> 
  </tr> 
  <tr> 
   <td>into table</td> 
   <td>表示加载到哪张表</td> 
  </tr> 
  <tr> 
   <td>student</td> 
   <td>表示具体的表</td> 
  </tr> 
  <tr> 
   <td>partition</td> 
   <td>表示上传到指定的分区</td> 
  </tr> 
 </tbody> 
</table>

#### 实操案例 ####

##### 创建表 #####

create table student(id string, name string) row format delimited fields terminated by '\t';

##### 加载本地文件到hive #####

load data local inpath '/opt/module/datas/student.txt' into table student;

hive (default)> load data local inpath '/opt/module/datas/student.txt' into table student;
    Loading data to table default.student
    Table default.student stats: [numFiles=1, totalSize=27]
    OK
    Time taken: 1.144 seconds
    hive (default)> select * from student;
    OK
    student.id      student.name
    1       zhangsan
    2       lisi
    3       wangwu
    Time taken: 0.085 seconds, Fetched: 3 row(s)

##### 加载HDFS文件到hive中 #####

上传文件到HDFS

dfs -put /opt/module/datas/student.txt /user/hive/warehouse;

加载HDFS数据

load data inpath '/user/hive/warehouse/student.txt' into table student;

加载数据覆盖表中已有的数据

load data inpath '/user/hive/warehouse/student.txt' overwrite into table student;

![2019-05-14-15578066641635.jpg][]

### 通过查询语句向表中插入数据（Insert） ###

#### 创建一个分区表 ####

create table student2(id int, name string) partitioned by (month string) row format delimited fields terminated by '\t'

#### 插入数据 ####

##### 基本插入 #####

insert into table  student2 partition(month='201905') values(1,'wangwu');

insert into 需要执行MR任务。

hive (default)> insert into table  student partition(month='201905') values(1,'wangwu');
    FAILED: SemanticException table is not partitioned but partition spec exists: {month=201905}
    hive (default)> insert into table  student2 partition(month='201905') values(1,'wangwu');
    Query ID = root_20190502135403_30a43b47-ec6a-4bbf-b407-50be007327d8
    Total jobs = 3
    Launching Job 1 out of 3
    Number of reduce tasks is set to 0 since there's no reduce operator
    Starting Job = job_1554120237694_0003, Tracking URL = http://hadoop101:8088/proxy/application_1554120237694_0003/
    Kill Command = /opt/module/hadoop-2.7.2/bin/hadoop job  -kill job_1554120237694_0003
    Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 0
    2019-05-02 13:54:30,454 Stage-1 map = 0%,  reduce = 0%
    2019-05-02 13:54:39,718 Stage-1 map = 100%,  reduce = 0%, Cumulative CPU 2.4 sec
    MapReduce Total cumulative CPU time: 2 seconds 400 msec
    Ended Job = job_1554120237694_0003
    Stage-4 is selected by condition resolver.
    Stage-3 is filtered out by condition resolver.
    Stage-5 is filtered out by condition resolver.
    Moving data to: hdfs://hadoop101:9000/user/hive/warehouse/student2/month=201905/.hive-staging_hive_2019-05-02_13-54-03_419_1815339772519319942-1/-ext-10000
    Loading data to table default.student2 partition (month=201905)
    Partition default.student2{month=201905} stats: [numFiles=1, numRows=1, totalSize=9, rawDataSize=8]
    MapReduce Jobs Launched: 
    Stage-Stage-1: Map: 1   Cumulative CPU: 2.4 sec   HDFS Read: 3652 HDFS Write: 94 SUCCESS
    Total MapReduce CPU Time Spent: 2 seconds 400 msec
    OK
    _col0   _col1
    Time taken: 41.99 seconds
    hive (default)> select * from student2;
    OK
    student2.id     student2.name   student2.month
    1       wangwu  201905
    Time taken: 0.973 seconds, Fetched: 1 row(s)

##### 基本模式插入（根据单张表查询结果） #####

insert overwrite table student2 partition(month='201904') 
    select id, name from student2 where month='201905';

hive (default)> insert overwrite table student2 partition(month='201904') select id, name from student2 where month='201905';
    Query ID = root_20190502135725_8518579c-6415-4312-ac66-85d523b85a74
    Total jobs = 3
    Launching Job 1 out of 3
    Number of reduce tasks is set to 0 since there's no reduce operator
    Starting Job = job_1554120237694_0004, Tracking URL = http://hadoop101:8088/proxy/application_1554120237694_0004/
    Kill Command = /opt/module/hadoop-2.7.2/bin/hadoop job  -kill job_1554120237694_0004
    Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 0
    2019-05-02 13:57:37,006 Stage-1 map = 0%,  reduce = 0%
    2019-05-02 13:57:46,786 Stage-1 map = 100%,  reduce = 0%, Cumulative CPU 1.57 sec
    MapReduce Total cumulative CPU time: 1 seconds 570 msec
    Ended Job = job_1554120237694_0004
    Stage-4 is selected by condition resolver.
    Stage-3 is filtered out by condition resolver.
    Stage-5 is filtered out by condition resolver.
    Moving data to: hdfs://hadoop101:9000/user/hive/warehouse/student2/month=201904/.hive-staging_hive_2019-05-02_13-57-25_946_1497692349000822439-1/-ext-10000
    Loading data to table default.student2 partition (month=201904)
    Partition default.student2{month=201904} stats: [numFiles=1, numRows=1, totalSize=9, rawDataSize=8]
    MapReduce Jobs Launched: 
    Stage-Stage-1: Map: 1   Cumulative CPU: 1.57 sec   HDFS Read: 3606 HDFS Write: 94 SUCCESS
    Total MapReduce CPU Time Spent: 1 seconds 570 msec
    OK
    id      name
    Time taken: 23.601 seconds
    hive (default)> select * from student2;
    OK
    student2.id     student2.name   student2.month
    1       wangwu  201904
    1       wangwu  201905
    Time taken: 0.162 seconds, Fetched: 2 row(s)

##### 多插入模式（根据多张表查询结果） #####

from student2 
    insert overwrite table student2 partition(month='201901')
    select id, name where month='201904'
    insert overwrite table student2 partition(month='201902')
    select id, name where month='201905';

hive (default)> from student2 
                  > insert overwrite table student2 partition(month='201901')
                  > select id, name where month='201904'
                  > insert overwrite table student2 partition(month='201902')
                  > select id, name where month='201905';
    Query ID = root_20190502140047_d0fc48db-4e42-43c1-a7ea-3fcb22acd77d
    Total jobs = 5
    Launching Job 1 out of 5
    Number of reduce tasks is set to 0 since there's no reduce operator
    Starting Job = job_1554120237694_0005, Tracking URL = http://hadoop101:8088/proxy/application_1554120237694_0005/
    Kill Command = /opt/module/hadoop-2.7.2/bin/hadoop job  -kill job_1554120237694_0005
    Hadoop job information for Stage-2: number of mappers: 1; number of reducers: 0
    2019-05-02 14:00:56,920 Stage-2 map = 0%,  reduce = 0%
    2019-05-02 14:01:05,735 Stage-2 map = 100%,  reduce = 0%, Cumulative CPU 1.97 sec
    MapReduce Total cumulative CPU time: 1 seconds 970 msec
    Ended Job = job_1554120237694_0005
    Stage-5 is selected by condition resolver.
    Stage-4 is filtered out by condition resolver.
    Stage-6 is filtered out by condition resolver.
    Stage-11 is selected by condition resolver.
    Stage-10 is filtered out by condition resolver.
    Stage-12 is filtered out by condition resolver.
    Moving data to: hdfs://hadoop101:9000/user/hive/warehouse/student2/month=201901/.hive-staging_hive_2019-05-02_14-00-47_034_306334479514022067-1/-ext-10000
    Moving data to: hdfs://hadoop101:9000/user/hive/warehouse/student2/month=201902/.hive-staging_hive_2019-05-02_14-00-47_034_306334479514022067-1/-ext-10002
    Loading data to table default.student2 partition (month=201901)
    Loading data to table default.student2 partition (month=201902)
    Partition default.student2{month=201901} stats: [numFiles=1, numRows=0, totalSize=9, rawDataSize=0]
    Partition default.student2{month=201902} stats: [numFiles=1, numRows=0, totalSize=9, rawDataSize=0]
    MapReduce Jobs Launched: 
    Stage-Stage-2: Map: 1   Cumulative CPU: 1.97 sec   HDFS Read: 5460 HDFS Write: 188 SUCCESS
    Total MapReduce CPU Time Spent: 1 seconds 970 msec
    OK
    id      name
    Time taken: 21.918 seconds
    hive (default)> select * from student2;
    OK
    student2.id     student2.name   student2.month
    1       wangwu  201901
    1       wangwu  201902
    1       wangwu  201904
    1       wangwu  201905
    Time taken: 0.31 seconds, Fetched: 4 row(s)

### 查询语句中创建表并加载数据（As Select） ###

根据查询结果创建表，查询的结果会添加到新创建的表中

create table if not exists student3 as select id, name from student;

hive (default)> create table if not exists student3
                  > as select id, name from student;
    Query ID = root_20190502140249_4f88537d-a1e3-4181-b659-42ba313491c8
    Total jobs = 3
    Launching Job 1 out of 3
    Number of reduce tasks is set to 0 since there's no reduce operator
    Starting Job = job_1554120237694_0006, Tracking URL = http://hadoop101:8088/proxy/application_1554120237694_0006/
    Kill Command = /opt/module/hadoop-2.7.2/bin/hadoop job  -kill job_1554120237694_0006
    Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 0
    2019-05-02 14:03:01,836 Stage-1 map = 0%,  reduce = 0%
    2019-05-02 14:03:10,732 Stage-1 map = 100%,  reduce = 0%, Cumulative CPU 1.2 sec
    MapReduce Total cumulative CPU time: 1 seconds 200 msec
    Ended Job = job_1554120237694_0006
    Stage-4 is selected by condition resolver.
    Stage-3 is filtered out by condition resolver.
    Stage-5 is filtered out by condition resolver.
    Moving data to: hdfs://hadoop101:9000/user/hive/warehouse/.hive-staging_hive_2019-05-02_14-02-49_692_5998422552783035794-1/-ext-10001
    Moving data to: hdfs://hadoop101:9000/user/hive/warehouse/student3
    Table default.student3 stats: [numFiles=1, numRows=3, totalSize=27, rawDataSize=24]
    MapReduce Jobs Launched: 
    Stage-Stage-1: Map: 1   Cumulative CPU: 1.2 sec   HDFS Read: 2905 HDFS Write: 99 SUCCESS
    Total MapReduce CPU Time Spent: 1 seconds 200 msec
    OK
    id      name
    Time taken: 24.143 seconds
    hive (default)> select * from student3;
    OK
    student3.id     student3.name
    1       zhangsan
    2       lisi
    3       wangwu
    Time taken: 0.06 seconds, Fetched: 3 row(s)

### 创建表时通过Location指定加载数据路径 ###

#### 创建表 ####

create table if not exists student4(
        id int, name string
    )
    row format delimited fields terminated by '\t'
    location '/user/hive/warehouse/student4';

#### 上传数据到HDFS ####

dfs -put /opt/module/datas/student.txt /user/hive/warehouse/student4;

#### 查询数据 ####

hive (default)> select * from student4;
    OK
    student4.id     student4.name
    1       zhangsan
    2       lisi
    3       wangwu
    Time taken: 0.06 seconds, Fetched: 3 row(s)

### Import数据到指定Hive表中 ###

**注意：先用export导出后，再将数据导入。**

import table student2 partition(month='201909') from
    '/user/hive/warehouse/export/student';

## 数据导出 ##

### Insert导出 ###

#### 基本用法 ####

insert overwrite local directory '/opt/module/datas/export/student' select * from student;

##### insert需要启动MR任务 #####

hive (default)> insert overwrite local directory '/opt/module/datas/export/student' select * from student;
    Query ID = root_20190502141319_edb4e6fd-386d-499e-b74f-c13ba9caa89d
    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_1554120237694_0007, Tracking URL = http://hadoop101:8088/proxy/application_1554120237694_0007/
    Kill Command = /opt/module/hadoop-2.7.2/bin/hadoop job  -kill job_1554120237694_0007
    Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 0
    2019-05-02 14:13:28,169 Stage-1 map = 0%,  reduce = 0%
    2019-05-02 14:13:35,777 Stage-1 map = 100%,  reduce = 0%, Cumulative CPU 1.06 sec
    MapReduce Total cumulative CPU time: 1 seconds 60 msec
    Ended Job = job_1554120237694_0007
    Copying data to local directory /opt/module/datas/export/student
    Copying data to local directory /opt/module/datas/export/student
    MapReduce Jobs Launched: 
    Stage-Stage-1: Map: 1   Cumulative CPU: 1.06 sec   HDFS Read: 2980 HDFS Write: 27 SUCCESS
    Total MapReduce CPU Time Spent: 1 seconds 60 msec
    OK
    student.id      student.name
    Time taken: 19.052 seconds

##### 查询结果 #####

[root@hadoop101 student]# pwd
    /opt/module/datas/export/student
    [root@hadoop101 student]# cat 000000_0 
    1zhangsan
    2lisi
    3wangwu

#### 将查询的结果格式化导出到本地 ####

insert overwrite local directory '/opt/module/datas/export/student1'
    ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t'  select * from student;

##### 查询结果 #####

[root@hadoop101 export]# cat student1/000000_0 
    1       zhangsan
    2       lisi
    3       wangwu

#### 将查询的结果导出到HDFS上(没有local) ####

insert overwrite directory '/user/hive/warehouse/export_stu'
    ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t' 
    select * from student;

![2019-05-14-15578103299969.jpg][]

### Hadoop命令导出到本地 ###

dfs -get /user/hive/warehouse/student2/month=201901/000000_0 
    /opt/module/datas/export/stu_201901.txt;

[root@hadoop101 datas]# ls export/
    stu_201901.txt  student  student1
    [root@hadoop101 datas]# cat export/stu_201901.txt 
    1       wangwu

### Hive Shell 命令导出 ###

基本语法：（hive -f/-e 执行语句或者脚本 > file）

hive -e 'select * from default.student;' > /opt/module/datas/export/student4.txt;

### Export导出到HDFS上 ###

export table default.student to '/user/hive/warehouse/export/student';

### Sqoop导出 ###

后续补充！

## 清除表中的数据（Truncate） ##

注意：Truncate只能删除管理表，不能删除外部表中数据

truncate table student;

[2019-05-14-15578066641635.jpg]: /images/20220201/dd16b96ec4ea4b8eb02555956b29c4b3.png
[2019-05-14-15578103299969.jpg]: /images/20220201/c3d5ade7eee245a59e3c10e9bb724a95.png