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https://issues.apache.org/jira/browse/CASSANDRA-9767?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14620554#comment-14620554
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Jonathan Ellis edited comment on CASSANDRA-9767 at 7/9/15 2:18 PM:
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NB: of course the example is incorrect as given, you would need GROUP BY for it
to make sense.
Edit: actually it is nonsense, if you are restricting to user_id=1 then there
is no need to select it as well. So not sure if he meant to give an example
needing GROUP BY or one needing HAVING or possibly both.
was (Author: jbellis):
(NB: of course the example is incorrect as given, you would need GROUP BY for
it to make sense.)
> Allow the selection of columns together with aggregates
> -------------------------------------------------------
>
> Key: CASSANDRA-9767
> URL: https://issues.apache.org/jira/browse/CASSANDRA-9767
> Project: Cassandra
> Issue Type: Wish
> Components: Core
> Environment: Cassandra 2.0.16
> Ubuntu 15.04
> Reporter: Ajay
> Assignee: Benjamin Lerer
> Priority: Minor
>
> Lets assume we have a column family as below:
> create table sample ( track_id int, user_id int, country varchar, primary key
> ((track_id), user_id));
> where track_id is the partition key.
> Now to aggregate the number of rows for a single track_id, we can query using
> CQL as below:
> select count(*) where track_id = 1 and user_id = 1;
> But that will return only the count. If we need the other columns along with
> the count, we cannot query as below as it throws error:
> select count(*), user_id from sample where track_id = 1 and user_id = 1;
> Bad Request: line 1:15 mismatched input ',' expecting K_FROM.
> In this case, all rows for a given track_id and user_id will have the same
> value for country. So we should be able to query as above. Also in SQL, it
> is possible to select columns along with aggregate functions.
> Though I know that Cassandra is not analytics (unlike Hadoop and Spark), we
> need some basic aggregate functions like min, max, avg etc....Though
> performance wise it might not be efficient, but it is better done in the
> cassandra side (as it uses native protocol) than we getting all rows in the
> client and doing the basic aggregation. It cannot used just as a data store
> (as garbage-in garbage-out). In that context, currently CQL is pretty
> limited. Just for getting data out of cassandra, we will have to spark though
> we will not be doing much analytics on it.
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