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Hive >> mail # user >> Does hive support nested queries?


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Re: Does hive support nested queries?
Yes, + is an operator.

t1
a b
1 2
3 4

and the result will be:
col
3
7
On Mon, Sep 17, 2012 at 4:43 PM, Amila Maha Arachchi
<[EMAIL PROTECTED]> wrote:
> Hi Bharath,
>
> Thanks for the reply. But I am confused while trying to understand the
> example in the wiki. Example says
>
>
> SELECT col
> FROM (
>   SELECT a+b AS col
>   FROM t1
> ) t2
>
>
> Can you please explain me what is a+b here. Are they two columns from table
> t1?
>
>
> Can you also tell me whether there is another way to achieve my original
> requirement.
>
>
> Thanks,
>
> Amila.
>
>
> On Mon, Sep 17, 2012 at 1:34 PM, bharath vissapragada
> <[EMAIL PROTECTED]> wrote:
>>
>> Hive supports subqueries only in the FROM clause as of now.
>>
>> https://cwiki.apache.org/confluence/display/Hive/LanguageManual+SubQueries
>>
>>
>> On Mon, Sep 17, 2012 at 1:03 PM, Amila Maha Arachchi
>> <[EMAIL PROTECTED]> wrote:
>>>
>>> Hi folks,
>>>
>>> I want to provide the output of a select query to a where clause of
>>> another query as shown below.
>>>
>>> select *
>>> from TableA
>>> where TA_timestamp > (select timestmp from TableB where id="hourDim")
>>>
>>> Is this possible in hive? When I try to execute this I get the following
>>> exception.
>>>
>>> If this is not possible, is there another way to achieve this?
>>>
>>> org.apache.hadoop.hive.ql.parse.ParseException: line 1:43 cannot
>>> recognize input near 'select' 'timestmp' 'from' in expression specification
>>>
>>> at
>>> org.apache.hadoop.hive.ql.parse.ParseDriver.parse(ParseDriver.java:438)
>>> at org.apache.hadoop.hive.ql.Driver.compile(Driver.java:417)
>>> at org.apache.hadoop.hive.ql.Driver.compile(Driver.java:337)
>>> at org.apache.hadoop.hive.ql.Driver.run(Driver.java:889)
>>> at
>>> org.apache.hadoop.hive.service.HiveServer$HiveServerHandler.execute(HiveServer.java:201)
>>> at
>>> org.apache.hadoop.hive.jdbc.HiveStatement.executeQuery(HiveStatement.java:187)
>>> at
>>> org.wso2.carbon.analytics.hive.impl.HiveExecutorServiceImpl$ScriptCallable.call(HiveExecutorServiceImpl.java:323)
>>> at
>>> org.wso2.carbon.analytics.hive.impl.HiveExecutorServiceImpl$ScriptCallable.call(HiveExecutorServiceImpl.java:224)
>>> at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
>>> at java.util.concurrent.FutureTask.run(FutureTask.java:138)
>>> at
>>> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
>>> at
>>> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
>>> at java.lang.Thread.run(Thread.java:662)
>>>
>>> Thanks in advance.
>>>
>>> Amila.
>>
>>
>>
>>
>> --
>> Regards,
>> Bharath .V
>> w:http://researchweb.iiit.ac.in/~bharath.v
>
>