postgres中的递归函数

Question

如何将下面的查询映射到 postgres 函数。

WITH RECURSIVE source (counter, product) AS (
SELECT
1, 1
UNION ALL
SELECT
counter + 1, product * (counter + 1)
FROM source
WHERE
counter < 10
)
SELECT counter, product FROM source;

我是 postgres 的新手。我想使用 PL/pgsql 函数实现相同的功能。

Answer 1

递归函数：

create or replace function recursive_function (ct int, pr int)
returns table (counter int, product int)
language plpgsql
as $$
begin
    return query select ct, pr;
    if ct < 10 then
        return query select * from recursive_function(ct+ 1, pr * (ct+ 1));
    end if;
end $$;

select * from recursive_function (1, 1);

循环函数：

create or replace function loop_function ()
returns table (counter int, product int)
language plpgsql
as $$
declare
    ct int;
    pr int = 1;
begin
    for ct in 1..10 loop
        pr = ct* pr;
        return query select ct, pr;
    end loop;
end $$;

select * from loop_function ();