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From "Sylvain Lebresne (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-11339) WHERE clause in SELECT DISTINCT can be ignored
Date Mon, 04 Apr 2016 12:27:25 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-11339?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15224024#comment-15224024
] 

Sylvain Lebresne commented on CASSANDRA-11339:
----------------------------------------------

I think for now we just want to reject {{DISTINCT}} queries with a {{WHERE}} clause. {{DISTINCT}}
can currently only select the partition key (and optionally static columns) so filtering on
other columns doesn't feel terribly useful to me in the first place. But even if we want to
allow it someday, it's quite a bit involved so the priority should be to fix the clearly incorrect
validation.

> WHERE clause in SELECT DISTINCT can be ignored
> ----------------------------------------------
>
>                 Key: CASSANDRA-11339
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-11339
>             Project: Cassandra
>          Issue Type: Bug
>          Components: CQL
>            Reporter: Philip Thompson
>            Assignee: Alex Petrov
>             Fix For: 2.1.x
>
>
> I've tested this out on 2.1-head. I'm not sure if it's the same behavior on newer versions.
> For a given table t, with {{PRIMARY KEY (id, v)}} the following two queries return the
same result:
> {{SELECT DISTINCT id FROM t WHERE v > X ALLOW FILTERING}}
> {{SELECT DISTINCT id FROM t}}
> The WHERE clause in the former is silently ignored, and all id are returned, regardless
of the value of v in any row. 
> It seems like this has been a known issue for a while:
> http://stackoverflow.com/questions/26548788/select-distinct-cql-ignores-where-clause
> However, if we don't support filtering on anything but the partition key, we should reject
the query, rather than silently dropping the where clause



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