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https://issues.apache.org/jira/browse/HIVE-6348?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16067372#comment-16067372
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Vineet Garg commented on HIVE-6348:
-----------------------------------
Looks like I am wrong. According to
https://mariadb.com/kb/en/mariadb/why-is-order-by-in-a-from-subquery-ignored/
bq. A "table" (and subquery in the FROM clause too) is - according to the SQL
standard - an unordered set of rows. Rows in a table (or in a subquery in the
FROM clause) do not come in any specific order. That's why the optimizer can
ignore the ORDER BY clause that you have specified. In fact, SQL standard does
not even allow the ORDER BY clause to appear in this subquery
> Order by/Sort by in subquery
> ----------------------------
>
> Key: HIVE-6348
> URL: https://issues.apache.org/jira/browse/HIVE-6348
> Project: Hive
> Issue Type: Bug
> Reporter: Gunther Hagleitner
> Assignee: Rui Li
> Priority: Minor
> Labels: sub-query
> Attachments: HIVE-6348.1.patch, HIVE-6348.2.patch, HIVE-6348.3.patch,
> HIVE-6348.4.patch
>
>
> select * from (select * from foo order by c asc) bar order by c desc;
> in hive sorts the data set twice. The optimizer should probably remove any
> order by/sort by in the sub query unless you use 'limit '. Could even go so
> far as barring it at the semantic level.
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