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From Nitin Pawar <nitinpawar...@gmail.com>
Subject RE: HBase table - distinct values
Date Thu, 11 Oct 2012 10:55:53 GMT
You may try define a hive table with hbase storage handler n then query it
..though response time will be slow based on how much data you have
On Oct 11, 2012 4:19 PM, <raviprasad.t@polarisft.com> wrote:

> Hi Anoop,
>  Thanks a lot for your reply,
>   Actually our requirment is just to count the distinct  deptno from  emp
> ( Hbase table),  We are running various pentaho jobs and we need to test
> the validity of the results, for that we need the below query.
>
> We need a query to select distinct deptno  from   emp  Hbase table.
>
> Example :-
>   HBase Table name :-  emp,  column_family :=  cf
>    Let us say  deptno is the field in the column family cf
>
> emp
> ----
> deptno
> 10
> 20
> 30
> 10
> 10
> 10
>
> The Result should be
> The  count (distinct deptno)  =  3
>
> We  need just the query to  know the count of  distinct  deptno .
>
> Thanks
> Regards
> Raviprasad. T
> Mobile :-  91- 9894769541
>
>
> -----Anoop Sam John <anoopsj@huawei.com> wrote: -----
> To: "user@hbase.apache.org" <user@hbase.apache.org>
> From: Anoop Sam John <anoopsj@huawei.com>
> Date: 10/11/2012 09:33AM
> Cc: "hbase-user@hadoop.apache.org" <hbase-user@hadoop.apache.org>
> Subject: RE: HBase table - distinct values
>
> Hi Ravi
>          If dept_no is a CF:qualifier, to know all the dept numbers
> (distinct or not) you need a full table scan. As Doug said if it is a
> frequent online query don't think MR is a good choice..  If the data in
> your emp table is huge a full table scan also wont be that good I feel....
>  Can you guys think about storing dept number in another table?  If you
> people need query like select <empdetails> from emp where dept_no=?  (this
> query also)  you can think about creating secondary index implementation
> and indexing dept_no... You can use index table for above query as well as
> the 1st one you asked about.  :)
>
> -Anoop-
> ________________________________________
> From: raviprasad.t@polarisFT.com [raviprasad.t@polarisFT.com]
> Sent: Wednesday, October 10, 2012 7:51 PM
> To: user@hbase.apache.org
> Cc: hbase-user@hadoop.apache.org; user@hbase.apache.org
> Subject: RE: HBase table - distinct values
>
> Hi,
>   Hbase table name  :- emp
>   Column family :- cf
>     Under the column family cf  we will be having the field name  deptno
>
>
> Regards
> Raviprasad. T
> Mobile :-  91- 9894769541
>
>
> -----Anoop Sam John <anoopsj@huawei.com> wrote: -----
> To: "user@hbase.apache.org" <user@hbase.apache.org>, "
> hbase-user@hadoop.apache.org" <hbase-user@hadoop.apache.org>
> From: Anoop Sam John <anoopsj@huawei.com>
> Date: 10/10/2012 06:18PM
> Subject: RE: HBase table - distinct values
>
> Hi
> Your schema? 'deptno'  is a cf:qualifier?
>
> -Anoop-
> ________________________________________
> From: raviprasad.t@polarisFT.com [raviprasad.t@polarisFT.com]
> Sent: Wednesday, October 10, 2012 4:29 PM
> To: user@hbase.apache.org; hbase-user@hadoop.apache.org
> Subject: HBase table - distinct values
>
> Hi all,
>   Is it possible to select distinct value from Hbase table.
>
> Example :-
>    what is the equivalant code for the below Oracle code  in Hbase  ?
>
>   Select count (distinct deptno) from emp ;
>
> Regards
> Raviprasad. T
>
>
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