var(col) built-in to go with avg(col) and count(col)
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Key: HIVE-165
URL: https://issues.apache.org/jira/browse/HIVE-165
Project: Hadoop Hive
Issue Type: Wish
Reporter: Adam Kramer
Priority: Minor
The last step in the unholy triumvirate of statistical built-ins is the
variance...we already have the n (count) and the mean (avg). I currently have
one reduce step that just computes mean/n/variance and writes it to a table, so
my guess is that this would be a pretty big speed increase. Not a huge deal
though, as computing the variance myself is trivial. (Average, variance, and n
can be co-computed in one pass)
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