argfirst() 🡒 boolean, process
true for the first value of the group according to the ordering. The group is optional. When the group is provided, the function returns
true once per group.
table T = with [| as N, as G |] [| 0, "b" |] [| 3, "a" |] [| 2, "a" |] [| 1, "a" |] T.A = argfirst() sort T.N T.B = argfirst() by T.G sort T.N show table "" a1c3 with T.N T.G T.A T.B