distinctapprox(T.‘a) 🡒 number, aggregator
The aggregator computes an approximation of how many distinct elements there are. Two elements
b are considered identical if
a == b. It is provided as an alternative to distinct, but with better performance. As a rule of thumb, this aggregator is intended for vectors beyond 1 million elements.
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 distinctapprox(T.A) group by gdim
number data types. It returns
0 on empty groups.
Advanced remark: The approximation is based on HyperLogLog.