hive中怎么退出所连接的数据库

发布网友 发布时间：2022-04-08 02:35

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懂视网 时间：2022-04-08 06:57

获得表的建表语句

hive (default)> show create table test;
OK
createtab_stmt
CREATE TABLE test(
id int)
ROW FORMAT SERDE
‘org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe’
STORED AS INPUTFORMAT
‘org.apache.hadoop.mapred.TextInputFormat’
OUTPUTFORMAT
‘org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat’
LOCATION
‘hdfs://nameservice1/user/hive/warehouse/test’
TBLPROPERTIES (
‘transient_lastDdlTime’=’1436799093’)
Time taken: 0.135 seconds, Fetched: 12 row(s)

创建内部表

其他获得表的信息

创建外部表

hive (default)> create external table testexttable(
  > name string comment ‘name value‘,
  > addr string comment ‘addr value‘
  > );
OK
Time taken: 10.172 seconds

create table if not exists testtable(
name string comment ‘name value‘,
addr string comment ‘addr value‘
)
row format delimited fields terminated by ‘	‘ lines terminated by ‘
‘ stored as textfile
;

加载数据

hive (default)> load data local inpath ‘/liguodong/hivedata/datatest’ overwrite into table testtable;

hive (default)> load data local inpath ‘/liguodong/hivedata/datatest’ into table testtable;
如果没有使用overwrite，则会再拷贝一份数据，不会覆盖原来的数据。

hive (default)> create external table if not exists employees(
  > name string,
  > salary string,
  > subordinates array<string>,
  > deductions map<string,float>,
  > address struct<street:string,city:string,state:string,zip:int>
  > )
  > row format delimited fields terminated by ‘	‘
  > collection items terminated by ‘,‘
  > map keys terminated by ‘:‘
  > lines terminated by ‘
‘
  > stored as textfile
  > location ‘/liguodong/data/‘
  > ;

查找表数据

hive> select * from employees;
OK
tony 1338 ["a1","a2","a3"] {"k1":1.0,"k2":2.0,"k3":3.0} {"street":"s1","city":"s2","state":"s3","zip":4}
mark 5453 ["a4","a5","a6"] {"k4":4.0,"k5":5.0,"k6":6.0} {"street":"s4","city":"s5","state":"s6","zip":6}
ivy 323 ["a7","a8","a9"] {"k7":7.0,"k8":8.0,"k9":9.0} {"street":"s7","city":"s8","state":"s9","zip":9}
Time taken: 10.204 seconds, Fetched: 3 row(s)

查树组
hive> select subordinates[1] from employees;
Total MapReduce CPU Time Spent: 2 seconds 740 msec
OK
a2
a5
a8
查map
hive> select deductions["k2"] from employees;

OK
2.0
NULL
NULL
Time taken: 75.812 seconds, Fetched: 3 row(s)

查结构体
hive> select address.city from employees;
Total MapReduce CPU Time Spent: 2 seconds 200 msec
OK
s2
s5
s8
Time taken: 75.311 seconds, Fetched: 3 row(s)

注意：select * 不执行mapreduce，只进行一个本地的查询。
而select 某个字段 生成一个job，执行mapreduce。

select * from employees;
select * from employees limit 10;

删除表

内部表删除，会连同hdfs存储的数据一同删除，而外部表删除，只会删除外部表的元数据信息。

hive (default)> drop table testtable;
OK
Time taken: 10.283 seconds
hive (default)> drop table testexttable;
OK
Time taken: 0.258 seconds

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Hive命令行常用操作（数据库操作，表操作）

标签：hive   数据库操作   命令行   表操作   

热心网友 时间：2022-04-08 04:05