postgresql postgres 中的递归函数
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时间：2020-10-21 01:26:21 来源:igfitidea点击:
Recursive function in postgres
提问by PL-SQL Developer1000
How to map below query to postgres function.
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;
I am new to postgres. I want to achieve same functionality using PL/pgsql function.
我是 postgres 的新手。我想使用 PL/pgsql 函数实现相同的功能。
回答by klin
Recursive function:
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);
Loop function:
循环功能：
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 ();
