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Hive - Create a Table delimited with Regex expression.

By Dinesh
Example -

I wanted to create a table with delimiter "~*". That can be done like below  -

CREATE external TABLE db1.t1(a string COMMENT '', b string COMMENT '', c string COMMENT '')
ROW FORMAT SERDE 'org.apache.hadoop.hive.serde2.RegexSerDe'
WITH SERDEPROPERTIES (
  'serialization.format' = '1',
  'input.regex' = '(.*?)~\\*(.*?)~\\*(.*)'
)
STORED AS
  INPUTFORMAT 'org.apache.hadoop.mapred.TextInputFormat'
  OUTPUTFORMAT 'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat'
LOCATION '\abc'

Note -

  1. In regex, I have to repeat the expression for as many columns as in table definition. For example, we had 3 columns.
  2. It can't be used for serialization that is. If I wanted to insert data in to the table I can't. It will throw exception.

Other way to do same is - 
create external TABLE `db1`.`t2` (col string) row format delimited location '\abc';

Note - 
  1. This will create a table and entire text will be in 1 column.
  2. Then, you can execute a query like below - 
    select arr[0], arr[1], arr[2] from (select split(col, '~\\*') as arr from `db1`.`t2`) T limit 10;
  3. Also, you can insert the data in this table without any hassle.

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