使用不同的critera连接同一张表上的不同行

Question

我尝试四处询问并进行谷歌搜索，最后得到了一个查询，该查询在所有可能的意义上都杀死了数据库。

我有3张桌子：

jiraissue保留有关jira票证（已分配给谁）的信息。

changegroup保留更改日期，票证的ID以及更改详细信息的ID。

changeitem包含更改ID，更改字段和新/旧值。

我想要以下输出：

[time_taken_to_resolve]，[assigned_date]，[resolve_date]，[jira_ticket_details_from_jiraissue]

条件是jiraissue.ASSIGNEE值。

我想出了以下几点：

SELECT TIMESTAMPDIFF(HOUR,a.assigned_date,b.resolved_date),a.*, b.* 
FROM jiraissue 
INNER JOIN (
    SELECT changegroup.CREATED as "assigned_date",changegroup.issueid as jid 
    FROM changegroup 
    JOIN changeitem ON changegroup.ID = changeitem.groupid 
    WHERE changeitem.FIELD="assignee"
    GROUP BY changegroup.issueid 
    ORDER BY changegroup.CREATED DESC 
) as a ON a.jid = jiraissue.id 
INNER JOIN ( 
    SELECT changegroup.CREATED as "resolved_date", changegroup.issueid as jid 
    FROM changegroup 
    JOIN jiraissue on changegroup.issueid = jiraissue.ID 
    JOIN changeitem ON changegroup.ID = changeitem.groupid 
    WHERE changeitem.FIELD="status" AND changeitem.NEWVALUE=5
    GROUP BY changegroup.issueid 
    ORDER BY changegroup.CREATED DESC 
) as b ON b.jid = jiraissue.id 
WHERE jiraissue.ASSIGNEE = "gangsta"; 

如果我使用特定的jiraissue.id ，则上面的查询有效，但如果我通过jiraissue.ASSIGNEE搜索（则进行运算），则jiraissue.ASSIGNEE 。

我也对最新的解决和分配日期感兴趣，可能有很多，但是我想要每个日期的最后一个。

任何帮助是极大的赞赏。

谢谢。

Answer 1

想到这一点，似乎可以解决问题：

SELECT TIMESTAMPDIFF(HOUR,a.assigned_date,b.resolved_date),a.*, b.*,jiraissue.*
FROM jiraissue
INNER JOIN (
  SELECT  MAX(changegroup.CREATED) as "assigned_date",changegroup.issueid as jid
  FROM changegroup 
  JOIN jiraissue as ji1 ON changegroup.issueid=ji1.id 
  JOIN changeitem ON changegroup.ID = changeitem.groupid 
  WHERE changeitem.FIELD="assignee" AND ji1.ASSIGNEE="gangsta" AND issuetype = 5 AND PRIORITY = 4
  GROUP BY changegroup.issueid
) as a ON a.jid = jiraissue.id
INNER JOIN (
  SELECT  MAX(changegroup.CREATED) as "resolved_date", changegroup.issueid as jid
  FROM changegroup 
  JOIN jiraissue as ji2 ON changegroup.issueid=ji2.id 
  JOIN changeitem ON changegroup.ID = changeitem.groupid 
  WHERE changeitem.FIELD="status" AND changeitem.NEWVALUE=5  AND ji2.ASSIGNEE="gangsta" AND issuetype = 5 AND PRIORITY = 4
  GROUP BY changegroup.issueid
) as b ON b.jid = jiraissue.id
ORDER BY b.resolved_date DESC;