FAQ
here are our result of multi-distinct:

hive> describe classes;
OK
name string
number string
class string
Time taken: 0.122 seconds
hive> select * from classes;
OK
1 11 8
2 22 12
4 212 2
5 232 23
6 22 2
7 22 2
3 333 13
3 33 3
4 133 32
5 33 3
Time taken: 0.154 seconds

hive> select count(distinct name), count(distinct number), class from
classes group by class;
....
1 1 12
1 1 13
3 2 2
1 1 23
2 1 3
1 1 32
1 1 8


2010/2/25 Mafish Liu <mafish@gmail.com>:
Hive does not support multi-distinct in one query.

We have implemented multi-distinct based on hive 0.4.2rc to our demand.
We don't know that if Hive is intresting in this feature.

2010/2/25 Jeff Zhang <zjffdu@gmail.com>:
Hi all,

I read the tutorial of Hive, and it says that "no two aggregations can have
different DISTINCT columns". Could anyone tell what is the reason ? Does the
following Distinct will been translate to map-reduce job or just do it
locally ?

INSERT OVERWRITE TABLE pv_gender_agg
SELECT pv_users.gender, count(DISTINCT pv_users.userid), count(DISTINCT
pv_users.ip)
FROM pv_users
GROUP BY pv_users.gender;

--
Best Regards

Jeff Zhang


--
Mafish@gmail.com


--
Mafish@gmail.com

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