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Apache hive - group by

Question asked by Lokesh on Sep 7, 2017
Latest reply on Sep 11, 2017 by maprcommunity

Hi All,


I do not know definite answer as to why below query would fail, however i read it somewhere 'Column Alias cannot be used in group by clause'. 


"time" is column which contains string value in the format [15/Jul/2009:14:58:59 - 0700], to extract "year" field write series of UDF's and used as below.


select year(from_unixtime(unix_timestamp(t1.time, '[dd/MMM/yyyy:HH:mm:ss Z]'))) as `year` , COUNT(*) from acceslogs as t1 group by `year`;


Need a confirmation why above query would fail. Thanks in advance.