如何将select查询的结果放入postgresql中的函数

CREATE FUNCTION my_function() RETURNS TABLE (column1 datatype1, column2 datatype2, ...) AS $$

DECLARE
    variable1 datatype1;
    variable2 datatype2;
    ...

SELECT column1, column2, ... INTO variable1, variable2, ...
FROM table_name
WHERE condition;

RETURN NEXT variable1, variable2, ...;

$$ LANGUAGE plpgsql;

CREATE FUNCTION my_function() RETURNS TABLE (column1 datatype1, column2 datatype2, ...) AS $$
DECLARE
    variable1 datatype1;
    variable2 datatype2;
BEGIN
    SELECT column1, column2, ... INTO variable1, variable2, ...
    FROM table_name
    WHERE condition;

    RETURN NEXT variable1, variable2, ...;
END;
$$ LANGUAGE plpgsql;

SELECT * FROM my_function();