Can I use an aggregation result as argument to a UDF during query?

I think only having clause is supported, udf on aggregation results is not supported afaik

The problem is we have sum(a)/sum(b) doing some rate calculation, but sum(b) can be 0, then the result will be NaN, when doing an order by, NaN will be ranked first, I want to fill NaN to 0 in this case.

Can you try adding

having sum(b) != 0

and see if it solves the problem?

adding having will filter the result, I actually want to fill NaN with 0.

You can also plug in your own UDF to replace

NaN

with

0

. Udf on aggregation results is supported (post-aggregation), e.g.

sum(a)/sum(b)

So a scalar UDF will work on post-aggregation, but groovy UDF will not work on post-aggregation?

Yes, groovy can only be used for record transform, but not post-aggregation as of now

OK, I will file an issue for this.