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From "Eugene Koifman (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HIVE-9481) allow column list specification in INSERT statement
Date Sat, 07 Feb 2015 02:27:34 GMT

     [ https://issues.apache.org/jira/browse/HIVE-9481?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Eugene Koifman updated HIVE-9481:
---------------------------------
    Status: Open  (was: Patch Available)

> allow column list specification in INSERT statement
> ---------------------------------------------------
>
>                 Key: HIVE-9481
>                 URL: https://issues.apache.org/jira/browse/HIVE-9481
>             Project: Hive
>          Issue Type: Bug
>          Components: Parser, Query Processor, SQL
>    Affects Versions: 0.14.0
>            Reporter: Eugene Koifman
>            Assignee: Eugene Koifman
>         Attachments: HIVE-9481.2.patch, HIVE-9481.patch
>
>
> Given a table FOO(a int, b int, c int), ANSI SQL supports insert into FOO(c,b) select
x,y from T.  The expectation is that 'x' is written to column 'c' and 'y' is written column
'b' and 'a' is set to NULL, assuming column 'a' is NULLABLE.
> Hive does not support this.  In Hive one has to ensure that the data producing statement
has a schema that matches target table schema.
> Since Hive doesn't support DEFAULT value for columns in CREATE TABLE, when target schema
is explicitly provided, missing columns will be set to NULL if they are NULLABLE, otherwise
an error will be raised.
> If/when DEFAULT clause is supported, this can be enhanced to set default value rather
than NULL.
> Thus, given {noformat}
> create table source (a int, b int);
> create table target (x int, y int, z int);
> create table target2 (x int, y int, z int);
> {noformat}
> {noformat}insert into target(y,z) select * from source;{noformat}
> will mean 
> {noformat}insert into target select null as x, a, b from source;{noformat}
> and 
> {noformat}insert into target(z,y) select * from source;{noformat}
> will meant 
> {noformat}insert into target select null as x, b, a from source;{noformat}
> Also,
> {noformat}
> from source insert into target(y,z) select null as x, * insert into target2(y,z) select
null as x, source.*;
> {noformat}
> and for partitioned tables, given
> {noformat}
> Given:
> CREATE TABLE pageviews (userid VARCHAR(64), link STRING, "from" STRING)
>   PARTITIONED BY (datestamp STRING) CLUSTERED BY (userid) INTO 256 BUCKETS STORED AS
ORC;
> INSERT INTO TABLE pageviews PARTITION (datestamp = '2014-09-23')(userid,link)  VALUES
('jsmith', 'mail.com');
> {noformat}



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