PostgreSQL 函数返回多种不同的类型

Question

函数是否可以返回多个不同的类型？

例子：

我有以下表格：games、games_rounds 和 games_players

现在要通过 id 加载完整游戏，我需要先从 games 加载它，然后通过执行 where game_id = $1 从 games_rounds 加载所有回合，然后对 games_players 执行相同操作，即 3对数据库的不同调用，能否以某种方式优化为函数？

简单演示：

// Basic schema (all game_id rows have an index on them):
    
create table games (id serial, state smallint, value int);

create table games_rounds (id serial, game_id int, outcome int);

create table games_users (game_id int, user_id int, order int);

// Example query to get full game data:

select id, state, value from games where id = 1

select id, outcome from games_rounds where game_id = 1

select user_id, order from games_users where game_id = 1

正如您在上面看到的games_users 和games_rounds 与games 的关系是多对一的，查询在实际应用中得到了简化，有更多的行和一些连接

Answer 1

如果我理解正确这是您想要做的，您可以使用refcursor

create procedure getGamedata(gameid int,result_one inout refcursor, result_two inout refcursor, result_two inout refcursor, result_three inout refcursor)
as
$$
begin
  open result_one for 
    select id, state, value from games where id = gameid;

  open result_two for 
    select id, outcome from games_rounds where game_id = gameid;

  open result_three for 
    select user_id, order from games_users where game_id = gameid;
end;
$$
language plpgsql;