上篇：第1章：Hive入门
1、Hive安装地址
1.1 Hive官网地址：
http://hive.apache.org/
1.2 文档查看地址：https://cwiki.apache.org/confluence/display/Hive/GettingStarted
1.3 下载地址：
http://archive.apache.org/dist/hive/
1.4 github地址
https://github.com/apache/hive
2、Hive安装部署
2.1 Hive安装及配置
（1）把apache-hive-1.2.1-bin.tar.gz上传到linux的/opt/software目录下
（2）解压apache-hive-1.2.1-bin.tar.gz到/opt/module/目录下面
[root@hadoop100 software]# tar -zxvf apache-hive-1.2.1-bin.tar.gz -C /opt/software/module/
（3）修改apache-hive-1.2.1-bin.tar.gz的名称为hive
（4）配置/etc/profile文件
[root@hadoop100 software]# vim /etc/profile
#HIVE_HONE
export HIVE_HOME=/opt/software/module/hive-1.2.1
export PATH=$JAVA_HOME/bin:$PATH:$HIVE_HOME/bin
保存退出！
[root@hadoop100 software]# source /etc/profile
2.2 Hadoop集群配置
（1）必须启动hdfs和yarn
[root@hadoop100 hadoop-2.7.2]# sbin/start-dfs.sh
[root@hadoop100 hadoop-2.7.2]# sbin/start-yarn.sh
（2）拷贝复制hive-env.sh.template文件重名hive-env.sh
[root@hadoop100 conf]# cp hive-env.sh.template hive-env.sh
编辑进入
HADOOP_HOME=/opt/hadoop/module/hadoop-2.7.2
export HIVE_CONF_DIR=/opt/software/module/hive-1.2.1/conf
接下来，启动hive
[root@hadoop100 bin]# hive
Logging initialized using configuration in jar:file:/opt/software/module/hive-1.2.1/lib/hive-common-1.2.1.jar!/hive-log4j.properties
启动成功！
2.3 Hive基本操作
（1）启动hive
[root@hadoop100 bin]# hive
Logging initialized using configuration in jar:file:/opt/software/module/hive-1.2.1/lib/hive-common-1.2.1.jar!/hive-log4j.properties
（2）查看数据库
hive> show databases;
OK
default
Time taken: 1.053 seconds, Fetched: 1 row(s)
（3）打开默认数据库
hive> use default;
OK
Time taken: 0.04 seconds
（4）显示default数据库中的表
hive> show tables;
OK
Time taken: 0.057 seconds
（5）创建一张表
hive> create table student(id int, name string);
OK
Time taken: 0.735 seconds
（6）显示数据库中有几张表
hive> show tables;
OK
student
Time taken: 0.025 seconds, Fetched: 1 row(s)
（7）查看表的结构
hive> desc student;
OK
id int
name string
Time taken: 0.516 seconds, Fetched: 2 row(s)
（8）向表中插入数据
hive> insert into student (id,name) values (1,'tom');
出现错误：
FAILED: SemanticException [Error 10293]: Unable to create temp file for insert values File /tmp/hive/root/2f5b7b9e-08b4-405a-ad42-05bc4722c13c/_tmp_space.db/Values__Tmp__Table__4/data_file could only be replicated to 0 nodes instead of minReplication (=1). There are 0 datanode(s) running and no node(s) are excluded in this operation.
at org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.chooseTarget4NewBlock(BlockManager.java:1547)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getNewBlockTargets(FSNamesystem.java:3107)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:3031)
at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.addBlock(NameNodeRpcServer.java:724)
at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.addBlock(ClientNamenodeProtocolServerSideTranslatorPB.java:492)
at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:616)
at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:969)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2049)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2045)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:422)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1657)
at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2043)
问题出现在：全为0，因为权限问题没有正常启动datanode
需要启动datanode，启动之后再查看：
[root@hadoop101 hadoop-2.7.2]# jps
13445 SecondaryNameNode
13288 DataNode
13882 NodeManager
13596 ResourceManager
14508 Jps
13165 NameNode
14078 RunJar
[root@hadoop101 hadoop-2.7.2]#
插入数据：
hive> insert into student (id,name) values (1,'tom');
Query ID = root_20191229171757_0f564e83-d1f2-45f2-8aa7-df6412462609
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_1577638672448_0001, Tracking URL = http://hadoop101:8088/proxy/application_1577638672448_0001/
Kill Command = /usr/local/hadoop/module/hadoop-2.7.2/bin/hadoop job -kill job_1577638672448_0001
Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 0
2019-12-29 17:18:19,060 Stage-1 map = 0%, reduce = 0%
2019-12-29 17:18:30,429 Stage-1 map = 100%, reduce = 0%, Cumulative CPU 2.45 sec
MapReduce Total cumulative CPU time: 2 seconds 450 msec
Ended Job = job_1577638672448_0001
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/student/.hive-staging_hive_2019-12-29_17-17-57_089_2845663360627823422-1/-ext-10000
Loading data to table default.student
Table default.student stats: [numFiles=1, numRows=1, totalSize=6, rawDataSize=5]
MapReduce Jobs Launched:
Stage-Stage-1: Map: 1 Cumulative CPU: 2.45 sec HDFS Read: 3555 HDFS Write: 77 SUCCESS
Total MapReduce CPU Time Spent: 2 seconds 450 msec
OK
Time taken: 36.286 seconds
（9）查询表中数据
hive> select * from student;
OK
1 tom
Time taken: 0.323 seconds, Fetched: 1 row(s)
（10）退出hive
hive> quit;
[root@hadoop101 bin]#
2.3 将本地文件导入Hive案例
需求
将本地/opt/module/datas/student.txt这个目录下的数据导入到hive的student(id int, name string)表中。
2.3.1 数据准备
（1）在/usr/local/hadoop/module目录下创建datas
[root@hadoop101 module]# mkdir datas
（1）在/usr/local/hadoop/module/datas目录下创建student.txt文件并添加数据
[root@hadoop101 datas]# touch student.txt
[root@hadoop101 datas]# vi student.txt
1001 zhangshan
1002 lishi
1003 zhaoliu
注意以tab键间隔。
2.3.2 Hive实际操作
（1）启动hive
[root@hadoop101 bin]# hive
（2）显示数据库
hive> show databases;
OK
default
Time taken: 1.036 seconds, Fetched: 1 row(s)
（3）使用default数据库
hive> use default;
OK
Time taken: 0.032 seconds
（4）显示default数据库中的表
hive> show tables;
OK
student
Time taken: 0.069 seconds, Fetched: 1 row(s)
（5）删除已创建的student表
hive> drop table student;
（6）创建student表, 并声明文件分隔符’\t’
hive> create table student(id int, name string) ROW FORMAT DELIMITED FIELDS TERMINATED
BY '\t';
OK
Time taken: 0.343 seconds
（7）加载/usr/local/hadoop/module/datas/student.txt 文件到student数据库表中。
hive> load data local inpath '/usr/local/hadoop/module/datas/student.txt' into table student;
Loading data to table default.student
Table default.student stats: [numFiles=1, totalSize=39]
OK
Time taken: 0.779 seconds
（8）Hive查询结果
select * from student;
OK
1001 zhangshan
1002 lishi
1003 zhaoliu
Time taken: 0.408 seconds, Fetched: 3 row(s)
注意：想要同时启动两个或两个以上的hive服务窗口，在本台的虚拟机必须需要安装mysql服务，否则，当开启第二个hive服务窗口就会报错！
由于自己的虚拟机是安装了mysql服务的所以启动二个hive服务窗口就不会报错，所以忽略过了！
配置只要是root用户+密码，在任何主机上都能登录MySQL数据库。基本步骤如下：
1．进入mysql，密码：123456
[root@hadoop101 mysql]# mysql -uroot -p
Enter password:
2．显示数据库
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| jdbc |
| mybatis |
| mysql |
| performance_schema |
| sys |
+--------------------+
6 rows in set (0.03 sec)
3．使用mysql数据库
mysql> use mysql;
Database changed
4．展示mysql数据库中的所有表
mysql> desc user;
+------------------------+-----------------------------------+------+-----+-----------------------+-------+
| Field | Type | Null | Key | Default | Extra |
+------------------------+-----------------------------------+------+-----+-----------------------+-------+
| Host | char(60) | NO | PRI | | |
| User | char(32) | NO | PRI | | |
| Select_priv | enum('N','Y') | NO | | N | |
| Insert_priv | enum('N','Y') | NO | | N | |
| Update_priv | enum('N','Y') | NO | | N | |
| Delete_priv | enum('N','Y') | NO | | N | |
| Create_priv | enum('N','Y') | NO | | N | |
| Drop_priv | enum('N','Y') | NO | | N | |
| Reload_priv | enum('N','Y') | NO | | N | |
| Shutdown_priv | enum('N','Y') | NO | | N | |
| Process_priv | enum('N','Y') | NO | | N | |
| File_priv | enum('N','Y') | NO | | N | |
| Grant_priv | enum('N','Y') | NO | | N | |
| References_priv | enum('N','Y') | NO | | N | |
| Index_priv | enum('N','Y') | NO | | N | |
| Alter_priv | enum('N','Y') | NO | | N | |
| Show_db_priv | enum('N','Y') | NO | | N | |
| Super_priv | enum('N','Y') | NO | | N | |
| Create_tmp_table_priv | enum('N','Y') | NO | | N | |
| Lock_tables_priv | enum('N','Y') | NO | | N | |
| Execute_priv | enum('N','Y') | NO | | N | |
| Repl_slave_priv | enum('N','Y') | NO | | N | |
| Repl_client_priv | enum('N','Y') | NO | | N | |
| Create_view_priv | enum('N','Y') | NO | | N | |
| Show_view_priv | enum('N','Y') | NO | | N | |
| Create_routine_priv | enum('N','Y') | NO | | N | |
| Alter_routine_priv | enum('N','Y') | NO | | N | |
| Create_user_priv | enum('N','Y') | NO | | N | |
| Event_priv | enum('N','Y') | NO | | N | |
| Trigger_priv | enum('N','Y') | NO | | N | |
| Create_tablespace_priv | enum('N','Y') | NO | | N | |
| ssl_type | enum('','ANY','X509','SPECIFIED') | NO | | | |
| ssl_cipher | blob | NO | | NULL | |
| x509_issuer | blob | NO | | NULL | |
| x509_subject | blob | NO | | NULL | |
| max_questions | int(11) unsigned | NO | | 0 | |
| max_updates | int(11) unsigned | NO | | 0 | |
| max_connections | int(11) unsigned | NO | | 0 | |
| max_user_connections | int(11) unsigned | NO | | 0 | |
| plugin | char(64) | NO | | mysql_native_password | |
| authentication_string | text | YES | | NULL | |
| password_expired | enum('N','Y') | NO | | N | |
| password_last_changed | timestamp | YES | | NULL | |
| password_lifetime | smallint(5) unsigned | YES | | NULL | |
| account_locked | enum('N','Y') | NO | | N | |
+------------------------+-----------------------------------+------+-----+-----------------------+-------+
45 rows in set (0.01 sec)
6．查询user表
mysql> select host,user,authentication_string from user;
+-----------+---------------+-------------------------------------------+
| host | user | authentication_string |
+-----------+---------------+-------------------------------------------+
| localhost | root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
| localhost | mysql.session | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| localhost | mysql.sys | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| % | root | *81F5E21E35407D884A6CD4A731AEBFB6AF209E1B |
+-----------+---------------+-------------------------------------------+
4 rows in set (0.01 sec)
7、 刷新
mysql>flush privileges;
Query OK, 0 rows affected (0.00 sec)
8、退出
mysql>quit;
3、配置Metastore到MySql
3.1 在/usr/local/hadoop/module/hive-1.2.1/conf/目录下创建一个hive-site.xml
[root@hadoop101 ~]# cd /usr/local/hadoop/module/hive-1.2.1/conf/
[root@hadoop101 conf]# touch hive-site.xml
[root@hadoop101 conf]# vi hive-site.xml
3.2 根据官方文档配置参数，拷贝数据到hive-site.xml文件中
https://cwiki.apache.org/confluence/display/Hive/AdminManual+MetastoreAdmin
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<property>
<name>javax.jdo.option.ConnectionURL</name>
<value>jdbc:mysql://localhost:3306/metastore?createDatabaseIfNotExist=true</value>
<description>JDBC connect string for a JDBC metastore</description>
</property>
<property>
<name>javax.jdo.option.ConnectionDriverName</name>
<value>com.mysql.jdbc.Driver</value>
<description>Driver class name for a JDBC metastore</description>
</property>
<property>
<name>javax.jdo.option.ConnectionUserName</name>
<value>root</value>
<description>username to use against metastore database</description>
</property>
<property>
<name>javax.jdo.option.ConnectionPassword</name>
<value>123456</value>
<description>password to use against metastore database</description>
</property>
</configuration>
3.3.1 在/user/local/java/mysql的目录下创建my-libs文件夹
[root@hadoop101 mysql]# mkdir my-libs
3.3.2 把java驱动包：mysql-connector-java-5.1.27.tar.gz上传到 /user/local/java/mysql/my-libs目录下，并进行解压
[root@hadoop101 mysql]# tar -zxvf mysql-connector-java-5.1.27.tar.gz -C /usr/local/java/mysql/my-libs/
[root@hadoop101 mysql-connector-java-5.1.27]# ll
total 1264
-rw-r--r-- 1 root root 47173 Oct 23 2013 build.xml
-rw-r--r-- 1 root root 222520 Oct 23 2013 CHANGES
-rw-r--r-- 1 root root 18122 Oct 23 2013 COPYING
drwxr-xr-x 2 root root 71 Dec 29 19:14 docs
-rw-r--r-- 1 root root 872303 Oct 23 2013 mysql-connector-java-5.1.27-bin.jar
-rw-r--r-- 1 root root 61423 Oct 23 2013 README
-rw-r--r-- 1 root root 63674 Oct 23 2013 README.txt
drwxr-xr-x 7 root root 67 Oct 23 2013 src
[root@hadoop101 mysql-connector-java-5.1.27]#
3.3.2 把解压包下的：mysql-connector-java-5.1.27-bin.jar文件拷贝到/usr/local/hadoop/module/hive-1.2.1/lib目录下
[root@hadoop101 mysql-connector-java-5.1.27]# cp mysql-connector-java-5.1.27-bin.jar /usr/local/hadoop/module/hive-1.2.1/lib/
3.3.3 由于修改过配置文件，退出重新进入
注意：
先启动mysql服务
[root@hadoop101 mysql]# mysql -uroot -p
Enter password:
显示数据库
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| jdbc |
| mybatis |
| mysql |
| performance_schema |
| sys |
+--------------------+
6 rows in set (0.00 sec)
再次启动hive服务
[root@hadoop101 hive-1.2.1]# bin/hive
Logging initialized using configuration in jar:file:/usr/local/hadoop/module/hive-1.2.1/lib/hive-common-1.2.1.jar!/hive-log4j.properties
hive>
接着，我们在mysql服务显示当前数据库，多了一个metastore
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| jdbc |
| metastore |
| mybatis |
| mysql |
| performance_schema |
| sys |
+--------------------+
7 rows in set (0.00 sec)
查看metastore数据库的内容
mysql> use metastore;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
显示数据库的表
mysql> show tables;
+---------------------------+
| Tables_in_metastore |
+---------------------------+
| BUCKETING_COLS |
| CDS |
| COLUMNS_V2 |
| DATABASE_PARAMS |
| DBS |
| FUNCS |
| FUNC_RU |
| GLOBAL_PRIVS |
| PARTITIONS |
| PARTITION_KEYS |
| PARTITION_KEY_VALS |
| PARTITION_PARAMS |
| PART_COL_STATS |
| ROLES |
| SDS |
| SD_PARAMS |
| SEQUENCE_TABLE |
| SERDES |
| SERDE_PARAMS |
| SKEWED_COL_NAMES |
| SKEWED_COL_VALUE_LOC_MAP |
| SKEWED_STRING_LIST |
| SKEWED_STRING_LIST_VALUES |
| SKEWED_VALUES |
| SORT_COLS |
| TABLE_PARAMS |
| TAB_COL_STATS |
| TBLS |
| VERSION |
+---------------------------+
29 rows in set (0.00 sec)
开第二个hive，启动hive服务
[root@hadoop101 bin]# hive
Logging initialized using configuration in jar:file:/usr/local/hadoop/module/hive-1.2.1/lib/hive-common-1.2.1.jar!/hive-log4j.properties
hive>
接着，显示当前数据库
hive> show databases;
OK
default
Time taken: 1.209 seconds, Fetched: 1 row(s)
hive>
4、Hive常用交互命令
4.1 Hive帮助命令：
[root@hadoop101 hive-1.2.1]# bin/hive -help
usage: hive
-d,--define <key=value> Variable subsitution to apply to hive
commands. e.g. -d A=B or --define A=B
--database <databasename> Specify the database to use
-e <quoted-query-string> SQL from command line
-f <filename> SQL from files
-H,--help Print help information
--hiveconf <property=value> Use value for given property
--hivevar <key=value> Variable subsitution to apply to hive
commands. e.g. --hivevar A=B
-i <filename> Initialization SQL file
-S,--silent Silent mode in interactive shell
-v,--verbose Verbose mode (echo executed SQL to the
console)
[root@hadoop101 hive-1.2.1]#
启动hive服务
[root@hadoop101 hive-1.2.1]# bin/hive
Logging initialized using configuration in jar:file:/usr/local/hadoop/module/hive-1.2.1/lib/hive-common-1.2.1.jar!/hive-log4j.properties
显示当前数据库与数据表
hive> show databases;
OK
default
Time taken: 1.006 seconds, Fetched: 1 row(s)
hive>
hive> show tables;
OK
Time taken: 0.069 seconds
hive>
创建一张student数据表
hive> create table student(id int,name string,age int)ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t' ;
OK
Time taken: 0.137 seconds
hive>
查询student数据表
hive> select * from student;
OK
1001 zhangshan NULL
1002 lishi NULL
1003 zhaoliu NULL
Time taken: 0.14 seconds, Fetched: 3 row(s)
hive>
注意：如元数据有的数据的信息，会直接加载进去
接下来，做常用交互命令
1．“-e”不进入hive的交互窗口执行sql语句
[root@hadoop101 hive-1.2.1]# bin/hive -e "select id from student;"
Logging initialized using configuration in jar:file:/usr/local/hadoop/module/hive-1.2.1/lib/hive-common-1.2.1.jar!/hive-log4j.properties
OK
1001
1002
1003
Time taken: 2.416 seconds, Fetched: 3 row(s)
[root@hadoop101 hive-1.2.1]#
2．“-f”执行脚本中sql语句
（1）在/usr/local/hadoop/module/datas目录下创建hivef.sql文件
[root@hadoop101 datas]# touch hivef.sql
[root@hadoop101 datas]# vim hivef.sql
select * from student;
（2）执行文件中的sql语句
[root@hadoop101 hive-1.2.1]# bin/hive -f /usr/local/hadoop/module/datas/hivef.sql
OK
1001 zhangshan NULL
1002 lishi NULL
1003 zhaoliu NULL
Time taken: 2.598 seconds, Fetched: 3 row(s)
[root@hadoop101 hive-1.2.1]#
（3）执行文件中的sql语句并将结果写入文件中
[root@hadoop101 hive-1.2.1]# bin/hive -f /usr/local/hadoop/module/datas/hivef.sql > /usr/local/hadoop/module/hive_result.txt
Logging initialized using configuration in jar:file:/usr/local/hadoop/module/hive-1.2.1/lib/hive-common-1.2.1.jar!/hive-log4j.properties
OK
Time taken: 2.452 seconds, Fetched: 3 row(s)
[root@hadoop101 hive-1.2.1]#
查看追加hive_result.txt文件信息
[root@hadoop101 module]# cat hive_result.txt
1001 zhangshan NULL
1002 lishi NULL
1003 zhaoliu NULL
[root@hadoop101 module]#
5、Hive其他命令操作
5.1 退出hive窗口：
hive(default)>exit;
hive(default)>quit;
在新版的hive中没区别了，在以前的版本是有的：
exit:先隐性提交数据，再退出；
quit:不提交数据，退出；
5.2 在hive cli命令窗口中如何查看hdfs文件系统
hive> dfs -ls /;
Found 2 items
drwx-wx-wx - root supergroup 0 2019-12-29 17:17 /tmp
drwxr-xr-x - root supergroup 0 2019-12-29 17:17 /user
hive>
5.3 在hive cli命令窗口中如何查看本地文件系统
hive> ! ls /usr/local/hadoop/module/datas；
hivef.sql
hive_result.txt
student.txt
5.3 查看在hive中输入的所有历史命令
[root@hadoop101 ~]# cat .hivehistory
show databases;
use default;
show tables;
create table student(id int, name string);
show tables;
desc student;
insert into student (id,name) values (1,'tom');
select * from student;
quit;
exit
show databases;
exit;
show databases;
show tables;
create table student(id int,name strung)row format delimited fields terminated by '\t'
show databases;
show tables;
create table student(id int,name strung)row format delimited fields terminated by '\t';
create table sqoop_test(NoViableAltException(26@[])
create table sqoop_test(id int,name string,age int)ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t' ;
create table hive_test(id int,name string,age int)ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t' ;
select * from hive_test;
create table student(id int,name string,age int)ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t' ;
select * from student;
exit;
6、Hive常见属性配置
6.1 Hive数据仓库位置配置
1）Default数据仓库的最原始位置是在hdfs上的/usr/local/hadoop/module/hive-1.2.1/conf
2）在仓库目录下，没有对默认的数据库default创建文件夹。如果某张表属于default数据库，直接在数据仓库目录下创建一个文件夹。
3）修改default数据仓库原始位置（将hive-default.xml.template如下配置信息拷贝到hive-site.xml文件中）。
<property>
<name>hive.cli.print.header</name>
<value>true</value>
</property>
<property>
<name>hive.cli.print.current.db</name>
<value>true</value>
</property>
配置完hive-site.xml文件之后，退出重新启动hive服务
hive> exit;
[root@hadoop101 hive-1.2.1]# bin/hive
Logging initialized using configuration in jar:file:/usr/local/hadoop/module/hive-1.2.1/lib/hive-common-1.2.1.jar!/hive-log4j.properties
hive (default)>
接下来，再进行查询student数据表
hive (default)> select * from student;
OK
student.id student.name student.age
1001 zhangshan NULL
1002 lishi NULL
1003 zhaoliu NULL
Time taken: 1.769 seconds, Fetched: 3 row(s)
hive (default)>
从上面得知，数据表的id也同时被查询出来了
在hive的配置文件 hive-default.xml.template ，找到这个参数是指定文件路径的，默认的数据仓库路径如下：
<property>
<name>hive.metastore.warehouse.dir</name>
<value>/user/hive/warehouse</value>
<description>location of default database for the warehouse</description>
</property>
7、Hive运行日志信息配置
7.1 首先，我们进入hive安装目录下的conf文件，找到hive-log4j.properties.template文件，并拷贝一份并重命名为hive-log4j.properties
[root@hadoop101 hive-1.2.1]# cd conf/
[root@hadoop101 conf]#
[root@hadoop101 conf]# cp hive-exec-log4j.properties.template hive-log4j.properties
[root@hadoop101 conf]#
7.2 编辑进入 hive-log4j.properties 文件
hive.log.dir=/usr/local/hadoop/module/hive-1.2.1/logs
保存退出！
注意：
8、参数配置方式
8.1 查看当前所有的配置信息
hive>set;
8.2 参数的配置三种方式
（1）配置文件方式
默认配置文件：==hive-default.xml ==
用户自定义配置文件：hive-site.xml
注意：用户自定义配置会覆盖默认配置。另外，Hive也会读入Hadoop的配置，因为Hive是作为Hadoop的客户端启动的，Hive的配置会覆盖Hadoop的配置。配置文件的设定对本机启动的所有Hive进程都有效。
（2）命令行参数方式
启动Hive时，可以在命令行添加==-hiveconf param=value==来设定参数。
例如：
hive (default)> set mapred.reduce.tasks;
mapred.reduce.tasks=-1
hive (default)>
3）参数声明方式
可以在HQL中使用SET关键字设定参数
例如：
hive (default)> set mapred.reduce.tasks=100;
hive (default)>
注意：仅对本次hive启动有效。
查看参数设置
hive (default)> set mapred.reduce.tasks;
mapred.reduce.tasks=100
hive (default)>
上述三种设定方式的优先级依次递增。即配置文件<命令行参数<参数声明。注意某些系统级的参数，例如log4j相关的设定，必须用前两种方式设定，因为那些参数的读取在会话建立以前已经完成了。
启动配置的参数：
先把原有的hive服务关闭之后，再重新启动
hive (default)> exit;
[root@hadoop101 hive-1.2.1]# bin/hive -hiveconf hive.cli.print.current.db=false
Logging initialized using configuration in file:/usr/local/hadoop/module/hive-1.2.1/conf/hive-log4j.properties
hive>
hive> set hive.cli.print.current.db=true;
hive (default)>
这种启动方式优先级会更高
