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Posted to issues@drill.apache.org by "Aman Sinha (JIRA)" <ji...@apache.org> on 2014/12/18 20:04:15 UTC
[jira] [Commented] (DRILL-1887) SQL Standard : NULL values are not
considered equal. But drill treats them as equal
[ https://issues.apache.org/jira/browse/DRILL-1887?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14252054#comment-14252054 ]
Aman Sinha commented on DRILL-1887:
-----------------------------------
It looks like an issue with hash joins. Merge join produces the right result. Odd that the existing test cases don't cover this.
> SQL Standard : NULL values are not considered equal. But drill treats them as equal
> -----------------------------------------------------------------------------------
>
> Key: DRILL-1887
> URL: https://issues.apache.org/jira/browse/DRILL-1887
> Project: Apache Drill
> Issue Type: Bug
> Reporter: Rahul Challapalli
>
> git.commit.id.abbrev=9dfa4a1
> Dataset1:
> {code}
> {
> "col1":1,
> "col2":"abc"
> }
> {
> "col1":2,
> "col2":null
> }
> {code}
> Dataset 2:
> {code}
> {
> "col1":1,
> "col2":null
> }
> {
> "col1":2,
> "col2":null
> }
> {
> "col1":2,
> "col2":"abc"
> }
> {code}
> Query :
> {code}
> select * from `a.json` a join `b.json` b on a.col2=b.col2;
> +------------+------------+------------+------------+
> | col1 | col2 | col10 | col20 |
> +------------+------------+------------+------------+
> | 1 | abc | 2 | abc |
> | 2 | null | 1 | null |
> | 2 | null | 2 | null |
> +------------+------------+------------+------------+
> {code}
> Most database engines treat 2 NULL values as not being equal. This makes it hard to compare DRILL's results against any Standard SQL engine. However I am not sure whether drill is intentionally designed to behave this way.
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