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From "Egbert van der Veen (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (DRILL-4684) Incorrect behavior when joining RDBMS table on itself
Date Wed, 18 May 2016 09:20:12 GMT

     [ https://issues.apache.org/jira/browse/DRILL-4684?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Egbert van der Veen updated DRILL-4684:
---------------------------------------
    Description: 
When joining a RDBMS table on itself (for instance; with a table that contains both subitems
and main items), Drill fails to correctly retrieve the result columns; the columns beloning
to the first instance that the table is referenced, are always NULL.

This has been tested using both MySQL and PostgreSQL databases as storage providers.

See attached screenshots for expected result (which works when queried directly against the
database), and the actual result through Drill

Code to reproduce:

{code:sql}
--create table
CREATE TABLE `join_test` (
  `id` int(11) NOT NULL,
  `type` varchar(50) DEFAULT NULL,
  `mainItem` int(11) DEFAULT NULL,
  `description` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `id` (`id`)
) ;

--insert testdata; one main item and two subitems. For subitems, column 'mainItem' is a reference
to the parent main item
INSERT INTO join_test (id, type, mainItem, description) VALUES (1, 'mainItem', null, 'First
main item');
INSERT INTO join_test (id, type, mainItem, description) VALUES (2, 'subItem', 1, 'First subitem
of first main item');
INSERT INTO join_test (id, type, mainItem, description) VALUES (3, 'subItem', 1, 'Second subitem
of first main item');

--perform query
SELECT main.type firsttype, main.description firstdescription, sub.type secondtype, sub.description
seconddescription 
FROM join_test sub
JOIN join_test main ON sub.mainItem = main.id
{code}

  was:
When joining a RDBMS table on itself (for instance; with a table that contains both subitems
and main items), Drill fails to correctly retrieve the result columns; the columns beloning
to the first instance of the table that is referenced, are always NULL.

This has been tested using both MySQL and PostgreSQL databases as storage providers.

See attached screenshots for expected result (which works when queried directly against the
database), and the actual result through Drill

Code to reproduce:

{code:sql}
--create table
CREATE TABLE `join_test` (
  `id` int(11) NOT NULL,
  `type` varchar(50) DEFAULT NULL,
  `mainItem` int(11) DEFAULT NULL,
  `description` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `id` (`id`)
) ;

--insert testdata; one main item and two subitems. For subitems, column 'mainItem' is a reference
to the parent main item
INSERT INTO join_test (id, type, mainItem, description) VALUES (1, 'mainItem', null, 'First
main item');
INSERT INTO join_test (id, type, mainItem, description) VALUES (2, 'subItem', 1, 'First subitem
of first main item');
INSERT INTO join_test (id, type, mainItem, description) VALUES (3, 'subItem', 1, 'Second subitem
of first main item');

--perform query
SELECT main.type firsttype, main.description firstdescription, sub.type secondtype, sub.description
seconddescription 
FROM join_test sub
JOIN join_test main ON sub.mainItem = main.id
{code}


> Incorrect behavior when joining RDBMS table on itself
> -----------------------------------------------------
>
>                 Key: DRILL-4684
>                 URL: https://issues.apache.org/jira/browse/DRILL-4684
>             Project: Apache Drill
>          Issue Type: Bug
>    Affects Versions: 1.6.0
>            Reporter: Egbert van der Veen
>         Attachments: actual result.png, expected result.png
>
>
> When joining a RDBMS table on itself (for instance; with a table that contains both subitems
and main items), Drill fails to correctly retrieve the result columns; the columns beloning
to the first instance that the table is referenced, are always NULL.
> This has been tested using both MySQL and PostgreSQL databases as storage providers.
> See attached screenshots for expected result (which works when queried directly against
the database), and the actual result through Drill
> Code to reproduce:
> {code:sql}
> --create table
> CREATE TABLE `join_test` (
>   `id` int(11) NOT NULL,
>   `type` varchar(50) DEFAULT NULL,
>   `mainItem` int(11) DEFAULT NULL,
>   `description` varchar(255) DEFAULT NULL,
>   PRIMARY KEY (`id`),
>   UNIQUE KEY `id` (`id`)
> ) ;
> --insert testdata; one main item and two subitems. For subitems, column 'mainItem' is
a reference to the parent main item
> INSERT INTO join_test (id, type, mainItem, description) VALUES (1, 'mainItem', null,
'First main item');
> INSERT INTO join_test (id, type, mainItem, description) VALUES (2, 'subItem', 1, 'First
subitem of first main item');
> INSERT INTO join_test (id, type, mainItem, description) VALUES (3, 'subItem', 1, 'Second
subitem of first main item');
> --perform query
> SELECT main.type firsttype, main.description firstdescription, sub.type secondtype, sub.description
seconddescription 
> FROM join_test sub
> JOIN join_test main ON sub.mainItem = main.id
> {code}



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