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Posted to user@hive.apache.org by Sarma Tangirala <tv...@gmail.com> on 2014/12/28 10:53:12 UTC
Row Counts From Multiple Tables
Hello,
I tried searching for this in the mailing list archive but could not find
an answer. I want to get the row counts from multiple tables, something
along the lines of
select count(t1.first_column), count(t2.first_column) from t1, t2;
But this query as is does not work.
Apologies if this has been explained before.
Thanks
Sarma
--
0 1 0
0 0 1
1 1 1
Re: Row Counts From Multiple Tables
Posted by Sarma Tangirala <tv...@gmail.com>.
Oh I understand how this done, but is there a way to avoid the union all
syntax? Nothing similar to mysql?
thanks!
On 28 December 2014 at 02:12, Seungbum Lee <de...@gmail.com> wrote:
> Hello Sarma,
>
> this will work.
>
> select sum(a.t1_cnt) as t1_cnt, sum(a.t2_cnt) as t2_cnt
> from (select count(first_column) as t1_cnt, 0 as t2_cnt
> from t1
> union all
> select 0 as t1_cnt, count(first_column) as t2_cnt
> from t2
> ) a
>
> good luck :)
>
> 2014-12-28 18:53 GMT+09:00 Sarma Tangirala <tv...@gmail.com>:
>
>> Hello,
>>
>> I tried searching for this in the mailing list archive but could not find
>> an answer. I want to get the row counts from multiple tables, something
>> along the lines of
>>
>> select count(t1.first_column), count(t2.first_column) from t1, t2;
>>
>> But this query as is does not work.
>>
>> Apologies if this has been explained before.
>>
>> Thanks
>> Sarma
>>
>>
>> --
>> 0 1 0
>> 0 0 1
>> 1 1 1
>>
>
>
--
0 1 0
0 0 1
1 1 1
Re: Row Counts From Multiple Tables
Posted by Seungbum Lee <de...@gmail.com>.
Hello Sarma,
this will work.
select sum(a.t1_cnt) as t1_cnt, sum(a.t2_cnt) as t2_cnt
from (select count(first_column) as t1_cnt, 0 as t2_cnt
from t1
union all
select 0 as t1_cnt, count(first_column) as t2_cnt
from t2
) a
good luck :)
2014-12-28 18:53 GMT+09:00 Sarma Tangirala <tv...@gmail.com>:
> Hello,
>
> I tried searching for this in the mailing list archive but could not find
> an answer. I want to get the row counts from multiple tables, something
> along the lines of
>
> select count(t1.first_column), count(t2.first_column) from t1, t2;
>
> But this query as is does not work.
>
> Apologies if this has been explained before.
>
> Thanks
> Sarma
>
>
> --
> 0 1 0
> 0 0 1
> 1 1 1
>