如何使用RECORD在PostgreSQL中返回多行？

Question

我正在尝试创建一个在多个表上运行SQL查询并从查询中输出结果表的函数.结果表将有多行.我在这方面遇到了很多困难,而且我已经阅读了建议使用的帖子,RETURN NEXT但我也无法让它工作.根据我的理解RECORD可以使用,因为它采用了输入数据的值.到目前为止,这是我的代码:

CREATE OR REPLACE FUNCTION
    most_docs()
RETURNS
    SETOF RECORD
AS $$
DECLARE
    result RECORD;
BEGIN
    CREATE VIEW MOSTDOC AS
    SELECT P.country, COUNT(P.country) AS cnt
    FROM Producer P, Movie M, ProducerMovie PM
    WHERE M.title = PM.title
    AND M.year = PM.year
    AND P.name = PM.name
    AND M.genre = 'Documentary'
    GROUP BY P.country;

    SELECT DISTINCT M.country INTO result
    FROM MOSTDOC M
    WHERE M.cnt = (SELECT MAX(M.cnt)
    FROM MOSTDOC M);

    RETURN result;
END;
$$ LANGUAGE plpgsql;

任何帮助将非常感激.谢谢.

---------- Word in Progress代码

CREATE OR REPLACE FUNCTION
    most_docs()
RETURNS
    SETOF RECORD
AS $$
DECLARE
result RECORD
BEGIN
    CREATE VIEW MOSTDOC AS
    SELECT P.country, COUNT(P.country) AS cnt
    FROM Producer P, Movie M, ProducerMovie PM
    WHERE M.title = PM.title
    AND M.year = PM.year
    AND P.name = PM.name
    AND M.genre = 'Documentary'
    GROUP BY P.country;

    RETURN QUERY SELECT DISTINCT M.country
    FROM MOSTDOC M
    WHERE M.cnt = (SELECT MAX(M.cnt)
    FROM MOSTDOC M);
END;
$$ LANGUAGE plpgsql;

Answer 1

根据这个答案，你需要的是：

RETURN QUERY SELECT DISTINCT......