Hive 实践（四）、Hive 语法归纳

野性酷女 2022-07-16 05:41 220阅读 0赞

hive 常用的语法：

## 1、 hive中创建表 ##

\#创建一个库表，表名为 cwqsolo， 含有2个字段 id， name，并且记录中各个字段的分割符为 ‘,’，在ascii中表示为 '\\054';

CREATE TABLE cwqsolo(id INT, name STRING)ROW FORMAT DELIMITED FIELDS TERMINATED BY '\\054';

##    创建分区表（内部表） ##

> create  table zc_bicc_isup_bdr (
        > 
        > opc                     int       ,    
        > 
        > dpc                     int                    , 
        > 
        > calling                 string                 ,      
        > 
        > calling_add_ind         int                   , 
        > 
        > called                  string                  ,
        > 
        > ori_called              string              , 
        > 
        > start_time              timestamp               ,  
        > 
        > alert_time              int                     ,    
        > 
        > talk_time               int                    , 
        > 
        > call_result             int                     ,      
        > 
        > rel_cause               int                 ,      
        > 
        > rel_dir                 int                 ,
        > 
        > gen_num                 string                 )
        > 
        > partitioned by (ptDate string)
        > 
        > ROW FORMAT DELIMITED
        > 
        > FIELDS TERMINATED BY ','
        > 
        > ;

注意： 如果没有 最后两行，在数据导入时可能会出现全是NULL的情况

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创建分区表（外部表）

## 2、修改库表结构 ##

修改库表的字段

\#修改字段名为ID的字段，修改后名称为 myid， string类型

ALTER TABLE cwqsolo CHANGE id myid String;

\#增加一个字段，字段名为 sex，性别

ALTER TABLE cwqsolo ADD COLUMNS ( sex STRING COMMENT 'sex type');

## 3、数据的装载 ##

可以建立一个文本文件，用，号分隔，然后使用load命令装载。

首先，建立一个文本文件：

[root@archive studydata]# vi  test1.txt
    1001,cwq,male
    1101,lxj,female

然后装载这个文本

hive> LOAD DATA LOCAL INPATH '/home/hadoop/hive/studydata/test1.txt' INTO TABLE cwqsolo;
    Loading data to table default.cwqsolo
    OK
    Time taken: 1.83 seconds
    hive> select  * from  cwqsolo;
    OK
    1001    cwq     male
    1101    lxj     female
    Time taken: 0.173 seconds, Fetched: 2 row(s)
    hive>

4、插入数据

1） 追加的方式插入数据，原有数据没有被修改

insert into  table cwqsolo values ( '1005', 'ddd','male' );

2） 重写的方式，旧的数据都被清除，指留下新的数据

insert overwrite table test_insert select * from test_table;

insert OVERWRITE  table cwqsolo values ( '1006', 'hhh','female' );
    WARNING: Hive-on-MR is deprecated in Hive 2 and may not be available in the future versions. Consider using a different execution engine (i.e. tez, spark) or using Hive 1.X releases.
    Query ID = root_20161007070952_4fc5c176-76da-40ff-8a4a-4522e2138441
    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_1475846838422_0002, Tracking URL = http://archive.cloudera.com:8088/proxy/application_1475846838422_0002/
    Kill Command = /opt/hadoop/hadoop-2.6.4//bin/hadoop job  -kill job_1475846838422_0002
    Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 0
    2016-10-07 07:44:25,570 Stage-1 map = 0%,  reduce = 0%
    2016-10-07 07:44:33,415 Stage-1 map = 100%,  reduce = 0%
    Ended Job = job_1475846838422_0002
    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://192.168.136.144:9000/user/hive/warehouse/cwqsolo/.hive-staging_hive_2016-10-07_07-44-15_130_2736379798501468939-1/-ext-10000
    Loading data to table default.cwqsolo
    MapReduce Jobs Launched: 
    Stage-Stage-1: Map: 1   Cumulative CPU: 2.6 sec   HDFS Read: 4598 HDFS Write: 87 SUCCESS
    Total MapReduce CPU Time Spent: 2 seconds 600 msec
    OK
    Time taken: 21.032 seconds
    hive> 
        > select * from cwqsolo;
    OK
    1006    hhh     female
    Time taken: 0.159 seconds, Fetched: 1 row(s)
    hive> 
        >

## 五、hive 执行 sql 文本 ##

1、 首先编辑一个sql文件，并上传到主机下。

2、执行 hive -f   路径/xxx.sql

如：

hive -f  /home/hadoop/hive/sql/creat_table_biss.sql

## 六、导出数据到本地文件 ##

hive> 
        > insert overwrite local directory '/home/data/cwq/'
        > 
        > select * from  zc_bicc_isup_bdr  where  calling= '13003097698';

在本地可以生成 000000\_0  文件，

可以制定分隔符：

insert overwrite local directory '/home/data/cwq/output1'row format delimited fields terminated by ',' select * from  zc_bicc_isup_bdr  where  calling= '13003097698';

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