Ok. There are 8 tables. Do you see any conditional match based on some keys? May be a well designed 'Left/Right' join provisioning would help you tackling your use case. You can also look at merge or union options. Once you are able to correlate those tables and design a query which would give you what you want, you can go ahead with file write feature (Insert overwrite directory) to save the data in your desired format.
On Tue 15 May, 2018, 11:03 PM Sowjanya Kakarala, <sowja...@agrible.com> wrote: > I am trying to fetch data from hive for 8tables at a time and save it in a > csv, so that our pipeline would read that csv which had 8tables data like: > > tb1 tb2 tb3 tb4 tb5 tb6 tb7 tb8 > 0.1 1.1 2.1 -1.1 -0.1 0.1 0.2 3.2 > 1.2 0.4 4.1 -2.1 -0.5 0.2 0.3 6.2 > and so on.... > > If I fetch one table at a time it will be hard to append all the 8 tables > data in one csv(not sure if we can do that and its time consuming). > > On Tue, May 15, 2018 at 12:20 PM, Alan Gates <alanfga...@gmail.com> wrote: > >> You are correct that Hive does not support "with recursive". A few more >> details of what you are trying to do would be helpful, since it's not clear >> why you need the iteration provided by "with recursive". If you really >> need the iteration I don't think Hive can do what you want. >> >> Alan. >> >> On Tue, May 15, 2018 at 9:34 AM, Sowjanya Kakarala <sowja...@agrible.com> >> wrote: >> >>> ok. but in my usecase join's/union's wont help. >>> Here is an example of my usecase from postgres, which I have to do it in >>> similar way for hive. >>> with recursive >>> a as (select col from tb1), >>> b as (select col from tb2), >>> c as (select col from tb3) >>> >>> select a,b,c from a,b,c; >>> >>> which output's me in a dataframe which i am writing to a csv and it >>> looks like >>> a b c >>> 0.1 0.2 0.3 >>> >>> where hive is not supporting `with rec` in same functionality as in >>> postgres and views are also not helping here. >>> >>> On Tue, May 15, 2018 at 11:19 AM, Alan Gates <alanfga...@gmail.com> >>> wrote: >>> >>>> In general this is done using joins, as in all SQL engines. A google >>>> search on "intro to SQL joins" will suggest a number of resources, for >>>> example >>>> https://www.essentialsql.com/get-ready-to-learn-sql-12-introduction-to-database-joins/ >>>> >>>> Alan. >>>> >>>> On Tue, May 15, 2018 at 7:37 AM, Sowjanya Kakarala < >>>> sowja...@agrible.com> wrote: >>>> >>>>> Hi all, >>>>> >>>>> Is there a way in hive that different tables data, can be read as in a >>>>> single query? >>>>> >>>>> example: >>>>> (something like) >>>>> select a,b from (select col1 from tbl1)a , (select col1 from tb2)b); >>>>> >>>>> output as : >>>>> a b >>>>> 0.1 0.2 >>>>> >>>>> Any help is appreciated. >>>>> >>>>> Thanks >>>>> Sowjanya >>>>> >>>> >>>> >>> >>> >>> -- >>> >>> >> > > > -- >
