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From Nitin Pawar <nitinpawar...@gmail.com>
Subject Re: date datatype in hive
Date Wed, 27 Jun 2012 09:52:23 GMT
soham,

the reason u r getting the error is there may be multiple names associated
with one country
so when you do  a group by there is no unique output to generate

so group by country, name will give you unique results

same is the case with select *

in case you want to sort the output you may try with order by country
instead of group by
if you want to omit duplicates you can use distinct

so try something like

select count(*), country from users_info group by country
select count(*) from users_info group by country
select distinct name, country from users_info order by country
select name, county from users_info group by country, name

all above should work unless i made a typo error :)



On Wed, Jun 27, 2012 at 3:11 PM, Soham Sardar <sohamsardartech@gmail.com>wrote:

> Thanks Bejoy and Nitin for replyin
> well now i got that thing ryt but then i have serious issues
>
> in hive querying like some of such queries are
>
> 1)  select * from users_info group by country;
>
> and this is giving me only the countries grouped alphabetically and
> not any other information
>
> 2) select name,country from users_info group by country;
>
> and this gives me an error
> FAILED: Error in semantic analysis: Line 1:7 Expression not in GROUP
> BY key 'name'
>
> can someone help me out with this :)
>
>
>
>
> On Wed, Jun 27, 2012 at 1:39 PM, Nitin Pawar <nitinpawar432@gmail.com>
> wrote:
> > soham,
> >
> > in your query
> > hive> select name from users_info  group by country;
> > FAILED: Error in semantic analysis: Line 1:7 Expression not in GROUP
> > BY key 'name'
> >
> > when you run group by it needs to be present in the select columns as
> well
> > thats what Bejoy suggested
> >
> > On Wed, Jun 27, 2012 at 12:05 PM, Soham Sardar <
> sohamsardartech@gmail.com>
> > wrote:
> >>
> >> Hey bejoy thats the problem i am not able to run the group by query in
> >> hive i dunno whether i m making a mistake or some thing
> >> see my previoius reply to this same thread i put up the same issue ...
> >>
> >>
> >> On Wed, Jun 27, 2012 at 12:02 PM, Bejoy KS <bejoy_ks@yahoo.com> wrote:
> >> > Hi Soham
> >> >
> >> > Rewrite your query with the columns in Group By included in Select as
> >> > well. Something like
> >> >
> >> > select country,name from users_info  group by country;
> >> >
> >> > Regards
> >> > Bejoy KS
> >> >
> >> > Sent from handheld, please excuse typos.
> >> >
> >> > -----Original Message-----
> >> > From: Soham Sardar <sohamsardartech@gmail.com>
> >> > Date: Wed, 27 Jun 2012 11:57:23
> >> > To: <user@hive.apache.org>; Bejoy Ks<bejoy_ks@yahoo.com>
> >> > Reply-To: user@hive.apache.org
> >> > Subject: Re: date datatype in hive
> >> >
> >> > And btw does group by works in hive because the same wuery i am
> >> > running in mysql and its working fine but its failing in hive
> >> >
> >> > select name from users_info  group by country;
> >> >
> >> > in mysql its working but whn i try to run it in hive its telling
> >> >
> >> > hive> select name from users_info  group by country;
> >> > FAILED: Error in semantic analysis: Line 1:7 Expression not in GROUP
> >> > BY key 'name'
> >> >
> >> > I wanna know why is it failing
> >> >
> >> >
> >> > On Wed, Jun 27, 2012 at 10:19 AM, Soham Sardar
> >> > <sohamsardartech@gmail.com> wrote:
> >> >> See Bejoy and Everyone ,
> >> >> I have two tables
> >> >> one users_info and one users_audit
> >> >> in hive ..
> >> >>
> >> >> hive> desc users_audit;
> >> >> OK
> >> >> id      int
> >> >> userid  int
> >> >> logtime string
> >> >>
> >> >> hive> desc users_info;
> >> >> OK
> >> >> id      int
> >> >> name    string
> >> >> age     int
> >> >> country string
> >> >> gender  string
> >> >> bday    string
> >> >>
> >> >> now i have given the description of the tables in hive
> >> >>
> >> >> my goal is to find:
> >> >> the maximum number of users loging - in at between a certain time
> >> >> frame say 1PM to 2PM- belonging to a specific country
> >> >>
> >> >> for example
> >> >> in between 1PM to 2PM there are 10000 users loging into and 5500 are
> >> >> from africa , then i need to print the names of all the users who are
> >> >> logged in between the time stamp and who are from africa ..
> >> >> the logtime in the users_audit table gives the login time and the
> >> >> names and country are from the users_info table .
> >> >>
> >> >> Can someone help me out with this . I am a new user in hive so would
> >> >> like some ones help !!!!!!
> >> >> Thanks in advance!!  :)
> >> >>
> >> >>
> >> >>
> >> >> On Tue, Jun 26, 2012 at 6:53 PM, Bejoy Ks <bejoy_ks@yahoo.com>
> wrote:
> >> >>>
> >> >>>
> >> >>> Hi Soham
> >> >>>
> >> >>> Hive Supports pretty much all the primitive data types including
> INT.
> >> >>> For a detaild list please refer
> >> >>>
> >> >>>
> https://cwiki.apache.org/confluence/display/Hive/Tutorial#Tutorial-PrimitiveTypes
> >> >>>
> >> >>> The only draw back as in common is when you have the data type
as
> >> >>> String you cannot use it directly on Mathematical functions.
> >> >>>
> >> >>> Your requirement can easily be satisfied with a few date functions
> on
> >> >>> String data itself.
> >> >>>
> >> >>> Regards
> >> >>> Bejoy KS
> >> >>>
> >> >>>
> >> >>> ________________________________
> >> >>> From: Soham Sardar <sohamsardartech@gmail.com>
> >> >>> To: user@hive.apache.org; user <user@sqoop.apache.org>
> >> >>> Sent: Tuesday, June 26, 2012 2:23 PM
> >> >>> Subject: date datatype in hive
> >> >>>
> >> >>> I have a native data type in mysql and i just imported it into
hive
> >> >>> and the data type of the column has now become string ..
> >> >>> Now i would like to know if there is any native data type in hive
> and
> >> >>> What are the pros and cons of using string type in hive rather
than
> >> >>> (int)(thats what i expect ) type
> >> >>>
> >> >>> And with the string type can i just run any type of queries like
> >> >>> print the names of the person which has the maximum number of users
> >> >>> between 1 PM and 3 PM
> >> >>>
> >> >>> and the table should have just name int(5) and login time (datetime
> )
> >> >>> {as per the mysql syntax}
> >
> >
> >
> >
> > --
> > Nitin Pawar
> >
>



-- 
Nitin Pawar

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