Hello Aniket, Thanks for the explanation. I have one more question that in SQL we write the multiple queries in which one query get executed and give the result to another query as a input. So, can we write something like that in Hive? I have also tried customs scripts in Hive but I am not getting that How to use it in block of queries. (Multiple queries)
Thanks and Regards, Bhavesh Shah On Thu, Jan 5, 2012 at 11:43 AM, Aniket Mokashi <aniket...@gmail.com> wrote: > Hi Bhavesh, > > [moving discussion to hive user list] > > I would suggest you to send your discussion to hive user list in order to > reach a broader audience. > > As per my understanding, in the query- map_script and reduce_script are > custom scripts that run as a streaming jobs. You are asking hive to run > map_script as mapper job on 3 columns to generate 3 new values- c1, c2, c3. > After this, hive will sort your records on c1 and c2 and distribute them to > reducers based on c3 values. 'reduce_scripts' will consume these 3 records > and generate 2 records to store in pv_users_reduced. > > Hope it helps. > > Thanks, > Aniket > > On Wed, Jan 4, 2012 at 8:55 PM, Bhavesh Shah <bhavesh25s...@gmail.com > >wrote: > > > Hello, > > I am new to hive. I want to write block of queries in Hive so that one > > query give result to another one like in SQL. > > > > I have also visited one link given below: > > http://karmasphere.com/ksc/hive-user-defined-functions.html > > > > In above link I am looking for functions but I get below one and I dont > > understand following things: > > > > USING 'map_script'USING 'reduce_script' > > > > in following block: > > > > > > FROM ( > > FROM pv_users > > MAP ( pv_users.userid, pv_users.date ) > > USING 'map_script' > > AS c1, c2, c3 > > DISTRIBUTE BY c2 > > SORT BY c2, c1) map_output > > INSERT OVERWRITE TABLE pv_users_reduced > > REDUCE ( map_output.c1, map_output.c2, map_output.c3 ) > > USING 'reduce_script' > > AS date, count; > > > > > > Pls can anyone tell what is the use of scripts and how to write block > > of queries in hive? > > > > > > > > > > -- > > Regards, > > Bhavesh Shah > > > > > > -- > "...:::Aniket:::... Quetzalco@tl" >
