you can create a table with key=deptno or every value that you need distinct value of it. scan of this table shows the distinct values.
On Thu, Oct 11, 2012 at 8:22 AM, Ramkrishna.S.Vasudevan < [email protected]> wrote: > Are you planning to use region splits? Can the rowkey have the deptno? > > Having dept no in another table, may be having a reverse mapping of deptno > to empno may be helpful too if such queries are frequent. > > Regards > Ram > > -----Original Message----- > > From: Anoop Sam John [mailto:[email protected]] > > Sent: Thursday, October 11, 2012 9:32 AM > > To: [email protected] > > Cc: [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]>, "hbase- > > [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= > >
