Create hive table using “as select” or “like” and

问题:

Is it possible to do a

create table <mytable> as select <query statement>

using

row format delimited fields terminated by '|';

or to do a

create table <mytable> like <other_table> row format delimited fields terminated by '|';

The Language Manual seems to indicate not.. but something tickles me I had achieved this in the past.

回答1:

Create Table as select (CTAS) is possible in Hive.

You can try out below command:

CREATE TABLE new_test 
row format delimited 
fields terminated by '|' 
STORED AS RCFile 
AS select * from source where col=1

1. Target cannot be partitioned table.
2. Target cannot be external table.
3. It copies the structure as well as the data

Create table like is also possible in Hive.

1. It just copies the source table definition.

回答2:

Let's say we have an external table called employee

hive> SHOW CREATE TABLE employee;
OK
CREATE EXTERNAL TABLE employee(
  id string,
  fname string,
  lname string, 
  salary double)
ROW FORMAT SERDE
  'org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe'
WITH SERDEPROPERTIES (
  'colelction.delim'=':',
  'field.delim'=',',
  'line.delim'='\n',
  'serialization.format'=',')
STORED AS INPUTFORMAT
  'org.apache.hadoop.mapred.TextInputFormat'
OUTPUTFORMAT
  'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat'
LOCATION
  'maprfs:/user/hadoop/data/employee'
TBLPROPERTIES (
  'COLUMN_STATS_ACCURATE'='false',
  'numFiles'='0',
  'numRows'='-1',
  'rawDataSize'='-1',
  'totalSize'='0',
  'transient_lastDdlTime'='1487884795')

1. To create a person table like employee

   CREATE TABLE person LIKE employee;

2. To create a person external table like employee

   CREATE TABLE person LIKE employee LOCATION 'maprfs:/user/hadoop/data/person';

3. then use DESC person; to see the newly created table schema.

回答3:

create table newtable as select column1, column2, column3 from oldtable