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From "Jonathan Ellis (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-2474) CQL support for compound columns
Date Mon, 22 Aug 2011 19:44:29 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-2474?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13088958#comment-13088958
] 

Jonathan Ellis commented on CASSANDRA-2474:
-------------------------------------------

bq. Rather than trying to support all this flexibility on the fly in Hive, why don't we let
users create transposed projections in the DML?

I like that idea, as the next best thing to finding a syntax that works well for both Hive
and CQL.

So for CQL, I think we're close with the "transposed" idea.  As explained above, "we have
"real" WHERE clauses we get all the benefits of regularity that implies."

I did note one problem with the transposed(x, y, z) syntax, though: you lose the ability to
compose with other functions in the SELECT clause.  Currently that just means count(), but
it's conceivable that we'd add scalar functions like sqrt(), or even aggregation like sum().

So I propose adding ".transposed" to the table name instead:

{noformat}
SELECT tweet_id, username, timestamp
FROM timeline.transposed 
WHERE user_id='jbellis'
LIMIT 50
{noformat}


> CQL support for compound columns
> --------------------------------
>
>                 Key: CASSANDRA-2474
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-2474
>             Project: Cassandra
>          Issue Type: Sub-task
>          Components: API, Core
>            Reporter: Eric Evans
>              Labels: cql
>             Fix For: 1.0
>
>
> For the most part, this boils down to supporting the specification of compound column
names (the CQL syntax is colon-delimted terms), and then teaching the decoders (drivers) to
create structures from the results.

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