Mysql sql语句的结果有问题

我使用SQL语句实现了以下场景， 我有一个问题分配给分组分诊、GX、GY：

组分类-->组GX

组GX-->组分类

组分类-->组分类

我只想在第一次将问题分配给组分流时提取，而忽略其余部分，我尝试过这样做，但结果总是不好（将问题分配给分流组时检索所有行）

SQL语句：

    select g.created ,ji.pkey as issueName
    from   changegroup g
    join   changeitem ci on (ci.groupid = g.id)
    join   jiraissue ji on (ji.id = g.issueid)
    join   project p on (p.id = ji.project)
    join   priority pr on (pr.id = ji.priority)
    where  ci.field = 'Group'
    and  ci.oldString = 'Triage' 
    and  p.pname = 'Test'
    and pr.pname='P3'
    and  ji.created between '2011-08-11 14:01:00' and  '2011-08-12 14:11:00'

语句的结果（如您所见，问题200被分配给组分类2次，因此请求检索2行）：

表更改组具有以下结构：

表changeitem具有以下结构：

---

试试这个。但这可能非常缓慢

select g.created, ji.pkey as issueName
from   changegroup g
join   jiraissue ji on (ji.id = g.issueid)
where (g.created, issueName) in (
 select min(g.created) ,ji.pkey as issueName
 from   changegroup g
 join   changeitem ci on (ci.groupid = g.id)
 join   jiraissue ji on (ji.id = g.issueid)
 join   project p on (p.id = ji.project)
 join   priority pr on (pr.id = ji.priority)
 where  ci.field = 'Group'
 and  ci.oldString = 'Triage' 
 and  p.pname = 'Test'
 and pr.pname='P3'
 and  ji.created between '2011-08-11 14:01:00' and  '2011-08-12 14:11:00'
 group by issueName
)