准备好的语句不存在，PostgreSQL

Question

我用这段代码创建了存储过程

CREATE PROCEDURE get_conferences_for_attendee
(
  IN start_time TIMESTAMP,
  IN end_time TIMESTAMP,
  IN email VARCHAR(255),
  IN deleted BOOLEAN
)
AS
$$
  SELECT c.localuuid, c.title, i.id, i.start_time, i.end_time, i.status, a.email, a.deleted
  FROM Conference c
  INNER JOIN Instance i ON i.conference_localuuid = c.localuuid
  INNER JOIN Conference_Attendees ca ON ca.conference_localuuid = c.localuuid
  INNER JOIN Attendee a ON ca.attendees_localuuid = a.localuuid
  WHERE i.start_time BETWEEN start_time AND end_time
  AND a.email = email
  AND a.deleted = deleted
$$ LANGUAGE SQL;

这回来了

创建程序

我可以看到我的程序

SELECT proname, prorettype
FROM pg_proc
WHERE pronamespace = (SELECT oid FROM pg_namespace WHERE nspname = 'public');


           proname            | prorettype 
------------------------------+------------
 get_conferences_for_attendee |       2278

当我尝试执行时，出现标题错误。

EXECUTE get_conferences_for_attendee ('2022-12-26T00:00:00', '2023-01-01T23:59:59', 'yacs.demo2@abc.com', false);

错误：准备好的语句“get_conferences_for_attendee”不存在

更新

我找到了一个解决方案，但我不确定这是否是创建它的正确方法。对我来说看起来太复杂了。

CREATE TYPE conference_record AS (                                                                                     
  localuuid VARCHAR(255),
  title VARCHAR(255),
  id VARCHAR(255),
  start_time TIMESTAMP,
  end_time TIMESTAMP,
  status VARCHAR(255),
  email VARCHAR(255),
  deleted BOOLEAN
);

CREATE FUNCTION get_conferences_for_attendee
(
  IN start_time TIMESTAMP,
  IN end_time TIMESTAMP,
  IN email VARCHAR(255),
  IN deleted BOOLEAN
)
RETURNS SETOF conference_record AS $$
  BEGIN
    RETURN QUERY
    SELECT c.localuuid, c.title, i.id, i.start_time, i.end_time, i.status, a.email, a.deleted
    FROM Conference c
    INNER JOIN Instance i ON i.conference_localuuid = c.localuuid
    INNER JOIN Conference_Attendees ca ON ca.conference_localuuid = c.localuuid
    INNER JOIN Attendee a ON ca.attendees_localuuid = a.localuuid
    WHERE i.start_time BETWEEN $1 AND $2
    AND a.email = $3
    AND a.deleted = $4;
  END;
$$ LANGUAGE plpgsql;

SELECT * FROM get_conferences_for_attendee ('2022-12-26T00:00:00', '2023-01-01T23:59:59', 'yacs.demo1@abc.com', false);

Answer 1

1. As pointed out in the comments，要使用程序，您需要CALL your_procedure();。

2. 您提供的代码看起来像是您试图从中获取某些东西，因此 function 更合适 - procedures 可以通过 out 和 inout 参数或副作用返回数据，例如将它们转储到外面的桌子。

3. 您稍后在编辑中添加的函数和类型定义看起来不错。如果您打算将其直接输入到表中，则无需定义自定义类型，而是指定 RETURNS SETOF your_target_table_name 或 RETURNS TABLE (LIKE your_target_table_name)。

   您也可以将其设为 LANGUAGE sql - 因为您没有使用任何特定于 plpgsql 的东西，所以您不需要随之而来的额外开销。您只需删除BEGIN RETURN QUERY 和END，只留下最基本的查询。

4. 您也可以为此使用常规的prepared statement：

   PREPARE get_conferences_for_attendee(
              TIMESTAMP,
              TIMESTAMP,
              VARCHAR(255),
              BOOLEAN                  ) AS
   SELECT 
       c.localuuid, 
       c.title, 
       i.id, 
       i.start_time, 
       i.end_time, 
       i.status, 
       a.email, 
       a.deleted
   FROM Conference c
   INNER JOIN Instance i               ON i.conference_localuuid = c.localuuid
   INNER JOIN Conference_Attendees ca  ON ca.conference_localuuid = c.localuuid
   INNER JOIN Attendee a               ON ca.attendees_localuuid = a.localuuid
   WHERE i.start_time BETWEEN $1 AND $2
   AND a.email = $3
   AND a.deleted = $4;
   

   并完全按照您最初计划的方式使用它，使用 EXECUTE：

   EXECUTE get_conferences_for_attendee(
              '2022-12-26T00:00:00', 
              '2023-01-01T23:59:59', 
              'yacs.demo1@abc.com', 
              false);
   

   Online demo