如何编写非参数化函数，以返回PostgreSQL中的表

Question

create or replace function demowhile_()
    returns table (id integer,name varchar(50))
        language 'plpgsql'
       as $$
    declare id integer;
    declare name varchar(50);
    begin
    CREATE temporary TABLE demo_(id integer,name varchar(50));
    CREATE temporary TABLE temp_ (id integer);
        insert into temp_ (select id from demo);
            while (select count(*) from temp_) <> 0
            loop
                id = (select top(1) id from temp_);
                name = (select name from demo where id = id);
                insert into demo_ values (id,name);
                delete from temp_ where id = id;
                end loop;
                return query select id,name from demo;
                end;
                $$;

****在执行时会出现错误，例如****

select * from demowhile();
**ERROR:  column reference "id" is ambiguous
LINE 1: insert into temp_ (select id,name from demo)
                                  ^
DETAIL:  It could refer to either a PL/pgSQL variable or a table column.
QUERY:  insert into temp_ (select id,name from demo)
CONTEXT:  PL/pgSQL function demowhile() line 9 at SQL statement
SQL state: 42702**

Answer 1

demowhile_() returns table (id integer,name varchar(50)基本上与 demowhile_(out id integer, out name varchar(50)) returns setof record

id输出列可以直接从功能中引用。然后，您还创建了一个名为id的函数变量。因此，当您将值分配给id时，您是分配给输出参数还是已声明的变量？PG不知道，所以您会遇到错误。

当然，简单的解决方案是给每个唯一名称。