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From DuyHai Doan <doanduy...@gmail.com>
Subject Re: CQL get unique row keys ?
Date Sat, 15 Feb 2014 18:51:36 GMT
Hello Andy

 Since C* 2.0.1 it is possible to list all distinct partition keys (not
clustering keys) with: SELECT DISTINCT pk FROM ....

 More info on the feature here:
https://issues.apache.org/jira/browse/CASSANDRA-4536

 This query is quite efficient because the key cache is used most of the
time.

 Regards

 Duy Hai DOAN



On Sat, Feb 15, 2014 at 6:05 PM, Andrew Cobley <a.e.cobley@dundee.ac.uk>wrote:

>  I may be missing something here, but is there a way in cql to get all
> unique row keys in a column family(table) ?
>
>  I've created a table like this:
>
>   CREATE TABLE totp (
>  artist varchar,
>  track varchar,
>   appearance_type varchar,
>   PRIMARY KEY ((artist),track)
>  ) WITH CLUSTERING ORDER BY (track asc);
>
>  and populated it with data.  As you can imagine, each artist can have
> multiple tracks .  Doing:
>
>  Select * from totp; will produce something like (with more artists of
> course)
>
>                     *The Tony Rich Project* |                             *Nobody
> Knows* |             *P/A*
>                             *Telly Savalas* |
>           *If* |           *PROMO*
>                              *Alice Cooper* |
>       *Elected* |            *DISC*
>                              *Alice Cooper* |                             *Hello
> Hooray* |           *PROMO*
>                              *Alice Cooper* |
>   *Hey Stupid* |           *Promo*
>                              *Alice Cooper* |                          *Lost
> In America* |             *P/A*
>                              *Alice Cooper* |                      *No
> More Mr.Nice Guy* |            *DISC*
>                              *Alice Cooper* |
>       *Poison* |           *Promo*
>                              *Alice Cooper* |                             *School's
> Out* |         *P/A V/T*
>                              *Alice Cooper* |
>   *Schools Out* |             *P/A*
>                              *Alice Cooper* |                       *Teenage
> Lament '74* |            *DISC*
>                   *Blackstreet Feat Dr.Dre* |
>   *No Diggity* |             *P/A*
>                                      *Nena* |                           *99
> Luftballons* |           *Promo*
>                                      *Nena* |                          *99
> Red Balloons* |             *P/A*
>  *and Select artist from totp; would produce:*
>
>                       *The Tony Rich Project*
>                             *Telly Savalas*
>                              *Alice Cooper*
>                              *Alice Cooper*
>                              *Alice Cooper*
>                              *Alice Cooper*
>                              *Alice Cooper*
>                              *Alice Cooper*
>                              *Alice Cooper*
>                              *Alice Cooper*
>                              *Alice Cooper*
>                    *Blackstreet Feat Dr.Dre*
>                                      *Nena*
>                                      *Nena*
>
>  *But of course what I really want is just the row keys *
>   *    The Tony Rich Project*
>                             *Telly Savalas*
>                              *Alice Cooper*
>                    *Blackstreet Feat Dr.Dre*
>                                      *Nena*
>
>  *Any idea if I can do this in CQL ?*
>
>  *Andy*
>
>
> The University of Dundee is a registered Scottish Charity, No: SC015096
>

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