http://wiki.apache.org/hadoop/Hive/LanguageManual/UDF
<http://wiki.apache.org/hadoop/Hive/LanguageManual/UDF>check conditional functions in the link above, it has the IF and CASE statement definitions. I am guessing some of them might not work with older version of Hive but not too sure. On Thu, Feb 3, 2011 at 11:38 PM, Amlan Mandal <[email protected]> wrote: > Actually I need to port some SQL queries to hive QL. > > Lets say I have hive table t which has columns mobile_no, cookie, ip, > access_id. > > Lets say I want to count unique users. My definition of of unique user = > all unique mobile numbers + all unique cookie (if for them mobile number not > present) + all unique ip ( where both mobile number and cookie is not > present) > > For example: > > mobile_no, cookie, ip , access_id > '9741112345', '', '1.2.3.4', 1 // may be from sms so cookie is not present > '9741112346', '', '1.2.3.4', 2 > '', 'aa', '1.2.3.4', 3 > '', 'bb', '1.2.3.4', 4 > '','', '1.2.3.5',5 > '','','1.2.3.4',6 > > There are 6 unique users . > > in MySQL we can handle like > > select count(distinct if(mobile_no !='', mobile_no, if(cookie != '', > cookie,ip)) from table. > > Is it possible to do the same thing in Hive in one query itself? > To be more specific can I do IF (control functions) in Hive? > > > Amlan >
