Hive 实践（四）、Hive 语法归纳
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 ','
>
> ;
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';