Why no two aggregations can have different DISTINCT columns ?

[Jeff Zhang]

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;


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Best Regards

Jeff Zhang