Support complete distinct usage for aggregate expressions #2406
Description
Is your feature request related to a problem or challenge? Please describe what you are trying to do.
Here are multiple aggregate expressions have not support distinct usage yet.
Though optimizer SingleDistinctToGroupBy (#1315) supports single distinct usage, there are more SQL scenes have not been covered, like
SELECT AVG(c1), SUM(DISTINCT c2) FROM test
I would like to take effort to work on the following tickets to complete distinct usage for aggregate expressions
-
sum(distinct)support #2405 - Introduce
sum_distinct()function to dataframe #2407 -
avg(distinct)support #2408 - Introduce
avg_distinct()function to dataframe #2409 -
var(distinct)support #2410 -
median(distinct)support #2411
(more to be added later)
Describe the solution you'd like
Adds specific aggregate expression support, like expressions::DistinctSum for sum(distinct)
Describe alternatives you've considered
No.
Additional context
No.