first

first(T.A : ‘a) 🡒 ‘a, ordered aggregator

The aggregator returns the first value for each group. It requires an ordering option, either sort or scan.

table T = with
  [| as A, as B |]
  [| "hello", "a" |]
  [| "hello", "a" |]
  [| "hello", "b" |]
  [| "world", "b" |]
  [| "world", "c" |]

table G[gdim] = by T.B

where T.B != "c"
  show table "" a1b4 with
    gdim
    first(T.A) sort T.A
    group by gdim

The ordering option can be applied to any ordered data type. When the group is empty, the default value for the data type is used.

See also