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可以帮助我解决这个重复问题，它为同一记录返回超过 1 个结果

我的查询：

SELECT DISTINCT ON(tickets.ticket_id,ticket_histories.created_at)
        ticket.id AS ticket_id,
        tickets.priority,
        tickets.title,
        tickets.company,
        tickets.ticket_statuse,
        tickets.created_at AS created_ticket,
        group_user.id AS group_id,
        group_user.name AS user_group,
        ch_history.description AS ch_description,
        ch_history.created_at AS ch_history
      FROM
        tickets
      INNER JOIN company ON (company.id = tickets.company_id)
      INNER JOIN (SELECT id,
        tickets_id,
        description,
        user_id,
        MAX(tickets.created_at) AS created_ticket
       FROM
        ch_history
       GROUP BY id,
        created_at,
        ticket_id,
        user_id,
        description
      ORDER BY created_at DESC LIMIT 1) AS ch_history ON (ch_history.ticket_id = ticket.id)
      INNER JOIN users ON (users.id = ch_history.user_id)
      INNER JOIN group_users ON (group_users.id = users.group_user_id)
      WHERE company = 15
      GROUP BY
        tickets.id,
        ch_history.created_at DESC;

我的查询结果，但返回 3 或 5 个具有不同历史的相同 id 我只想返回每张票的 1 个 id，并且只返回每个刻度的最后记录历史

 ticket_id | priority |                title                | company_id | ticket_statuse |       created_ticket       |                     company                          |  user_group     | group_id |     ch_description      |        ch_history       
            -----------+------------+--------------------------------------+------------+-----------------+----------------------------+------------------------------------------------------+-----------------+----------+------------------------+----------------------------
                 49713 |          2 | REMOVE DATA                       |      1 | t               | 2019-12-09 17:50:35.724485 | SAME COMPANY                                         | people          |        5 | TEST 1                  | 2019-12-10 09:31:45.780667
                 49706 |          2 | INCLUDE DATA                      |      1 | f               | 2019-12-09 09:16:35.320708 | SAME COMPANY                                         | people          |        5 | TEST 2                  | 2019-12-10 09:38:52.769515
                 49706 |          2 | ANY TITLE                         |      1 | f               | 2019-12-09 09:16:35.320708 | SAME COMPANY                                         | people          |        5 | TEST 3                  | 2019-12-10 09:39:22.779473
                 49706 |          2 | NOTING ELSE MAT                   |      1 | f               | 2019-12-09 09:16:35.320708 | SAME COMPANY                                         | people          |        5 | TESTE 4                 | 2019-12-10 09:42:59.50332
                 49706 |          2 | WHITESTRIPES                      |      1 | f               | 2019-12-09 09:16:35.320708 | SAME COMPANY                                         | people          |        5 | TEST 5                  | 2019-12-10 09:44:30.675434

想返回如下

 ticket_id | priority |                title                | company_id | ticket_statuse |       created_ticket       |                     company                       |  user_group     | group_id |     ch_description      |        ch_history       
-----------+------------+--------------------------------------+------------+-----------------+----------------------------+------------------------------------------------------+-----------------+----------+------------------------+----------------------------
     49713 |          2 | REMOVE DATA                       |      1 | t               | 2019-12-09 17:50:10.724485 | SAME COMPANY                                         | people          |        5 | TEST 1                  | 2020-01-01 18:31:45.780667
     49707 |          2 | INCLUDE DATA                      |      1 | f               | 2019-12-11 19:22:21.320701 | SAME COMPANY                                         | people          |        5 | TEST 2                  | 2020-02-05 16:38:52.769515
     49708 |          2 | ANY TITLE                         |      1 | f               | 2019-12-15 07:15:57.320950 | SAME COMPANY                                         | people          |        5 | TEST 3                  | 2020-02-06 07:39:22.779473
     49709 |          2 | NOTING ELSE MAT                   |      1 | f               | 2019-12-16 08:30:28.320881 | SAME COMPANY                                         | people          |        5 | TESTE 4                 | 2020-01-07 11:42:59.50332
     49701 |          2 | WHITESTRIPES                      |      1 | f               | 2019-12-21 11:04:00.320450 | SAME COMPANY                                         | people          |        5 | TEST 5                  | 2020-01-04 10:44:30.675434

我想返回如下所示，看到字段 ch_description 和 ch_history 只带最近的记录，并且只带上列出的每张票的最后一条，没有重复我想带这种方式可以帮助我。

4

1 回答 1

1

我突然想到两件事：

  1. 您已将“created at”列为“distinct on”的一部分，这将固有地为每个票证 ID 提供多行（除非恰好只有一个）

  2. 不同的 on 应该使票证历史记录上的子查询变得不必要......即使您选择这样做，您也将再次进入“创建于”列，这将为您提供多个结果。如果您选择这种方法，理想的子查询应该是按ticket_id 并且仅按ticket_id 分组。

略相关：

  1. 子查询的另一种方法是分析函数（窗口函数），但我将把它留到另一天。

我认为您想要的查询，根据历史表的 created_at 字段，每个ticket_id 将为您提供一行，如下所示：

select distinct on (t.id)
  <your fields here>
from
  tickets t
  join company c on t.company_id = c.id
  join ch_history ch on ch.ticket_id = t.id
  join users u on ch.user_id = u.ud
  join group_users g on u.group_user_id = g.id
where
  company = 15
order by
  t.id, ch.created_at  -- this is what tells distinct on which record to choose
于 2020-02-17T16:01:11.270 回答