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 <[email protected]> wrote: ----- To: "[email protected]" <[email protected]> From: Anoop Sam John <[email protected]> Date: 10/11/2012 09:33AM Cc: "[email protected]" <[email protected]> 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: [email protected] [[email protected]] Sent: Wednesday, October 10, 2012 7:51 PM To: [email protected] Cc: [email protected]; [email protected] 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 <[email protected]> wrote: ----- To: "[email protected]" <[email protected]>, "[email protected]" <[email protected]> From: Anoop Sam John <[email protected]> Date: 10/10/2012 06:18PM Subject: RE: HBase table - distinct values Hi Your schema? 'deptno' is a cf:qualifier? -Anoop- ________________________________________ From: [email protected] [[email protected]] Sent: Wednesday, October 10, 2012 4:29 PM To: [email protected]; [email protected] 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 This e-Mail may contain proprietary and confidential information and is sent for the intended recipient(s) only. If by an addressing or transmission error this mail has been misdirected to you, you are requested to delete this mail immediately. You are also hereby notified that any use, any form of reproduction, dissemination, copying, disclosure, modification, distribution and/or publication of this e-mail message, contents or its attachment other than by its intended recipient/s is strictly prohibited. Visit us at http://www.polarisFT.com This e-Mail may contain proprietary and confidential information and is sent for the intended recipient(s) only. If by an addressing or transmission error this mail has been misdirected to you, you are requested to delete this mail immediately. You are also hereby notified that any use, any form of reproduction, dissemination, copying, disclosure, modification, distribution and/or publication of this e-mail message, contents or its attachment other than by its intended recipient/s is strictly prohibited. Visit us at http://www.polarisFT.com This e-Mail may contain proprietary and confidential information and is sent for the intended recipient(s) only. If by an addressing or transmission error this mail has been misdirected to you, you are requested to delete this mail immediately. You are also hereby notified that any use, any form of reproduction, dissemination, copying, disclosure, modification, distribution and/or publication of this e-mail message, contents or its attachment other than by its intended recipient/s is strictly prohibited. Visit us at http://www.polarisFT.com
