The aggregator indicates how many distinct elements there are. Two elements a and b are considered identical if a == b.
Example:
table T = with
[| as A, as B |]
[| 0, "a" |]
[| 0, "a" |]
[| 0, "b" |]
[| 1, "b" |]
[| 1, "c" |]
table G[gdim] = by T.B
where T.B != "c"
show table "" a1b4 with
gdim
distinct(T.A)
group by gdim
The aggregator distinct supports all the data types. It returns 0 on empty groups.