Github user JamesRTaylor commented on the pull request:
https://github.com/apache/incubator-phoenix/pull/30#issuecomment-44477648
I did a bit more research on first_value, last_value, and nth_value and it
turns out they're not aggregate functions - they're only valid for non
aggregate queries. They also use a slightly different syntax - FIRST_VALUE(col)
OVER (ORDER BY other_col).
So these functions in this pull *are* aggregate functions and there's no
standard SQL equivalent I can find. Some SQL dialects that have a FIRST and
LAST function - maybe we should rename these as FIRST,LAST,NTH? Or perhaps it's
ok to keep as-is since it's using the WITHIN GROUP syntax which would be
different for the analytics version of these with the same name.
Any opinions?
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