ydb/yt/yql/tests/sql/suites/aggr_factory/udaf.sql

/* syntax version 1 */
/* postgres can not */
-- count example
$create = ($_item, $_parent) -> { return 1 };
$add = ($state, $_item, $_parent) -> { return 1 + $state };
$merge = ($state1, $state2) -> { return $state1 + $state2 };
$get_result = ($state) -> { return $state };
$serialize = ($state) -> { return $state };
$deserialize = ($state) -> { return $state };
$default = 0;

$f = AGGREGATION_FACTORY("udaf", $create, $add, $merge, $get_result, $serialize, $deserialize, $default);
$t = AsList(AsStruct(1 as a),AsStruct(2 as a));

select Yql::Aggregate($t, AsTuple(), AsTuple(AsTuple(AsAtom("res"), $f(
    ListItemType(TypeOf($t)), ($z)->{return $z.a}))));

$t = AsList(AsStruct(1/0 as a),AsStruct(2/0 as a));
select Yql::Aggregate($t, AsTuple(), AsTuple(AsTuple(AsAtom("res"), $f(
    ListItemType(TypeOf($t)), ($z)->{return $z.a}))));

use plato;
insert into @a select * from as_table($t);
commit;
select AGGREGATE_BY(a,$f) from @a;
select AGGREGATE_BY(distinct a,$f) from @a;