Hive 实践（四）、Hive 语法归纳

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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

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.txt1001,cwq,male1101,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.cwqsoloOKTime taken: 1.83 secondshive> select  * from  cwqsolo;OK1001    cwq     male1101    lxj     femaleTime 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-4522e2138441Total jobs = 3Launching Job 1 out of 3Number of reduce tasks is set to 0 since there's no reduce operatorStarting 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_0002Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 02016-10-07 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_0002Stage-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-10000Loading data to table default.cwqsoloMapReduce Jobs Launched: Stage-Stage-1: Map: 1   Cumulative CPU: 2.6 sec   HDFS Read: 4598 HDFS Write: 87 SUCCESSTotal MapReduce CPU Time Spent: 2 seconds 600 msecOKTime taken: 21.032 secondshive>     > select * from cwqsolo;OK1006    hhh     femaleTime 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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