SQL>为单个结果选择多行

Question

我有上面的表，我需要做的是，例如基于该图像，返回的单行将显示：

Ticket ID |       Created       |       Assigned      | Time Difference  
    2     | 2015-05-31 09:18:44 | 2015-06-03 10:05:00 | $MATH_RESULT

该图像仅显示了一个示例，但我想让它返回同时具有“分配”时间和“创建”时间的每张票证。

我不是DBA，这超出了我的有限知识。 有人可以帮我实现这一目标吗？

Answer 1

您可以使用join为状态为“创建”的行查找状态为“已分配”的行：

select  c.ticket_id
,       c.timestamp
,       a.timestamp
,       datediff(a.timestamp, c.timestamp)
from    ticket c
join    ticket a
on      c.ticket_id = a.ticket_id
where   c.state = 'created'
        and a.state = 'assigned'

Answer 2

http://sqlfiddle.com/#!9/cf498/3

SELECT t.ticket_id,t.timestamp as created, t1.timestamp as assigned, (t1.timestamp - t.timestamp) as delay
FROM table1 t
LEFT JOIN table1 t1
ON t.ticket_id = t1.ticket_id
  AND t1.state = 'assigned'
WHERE t.ticket_id = 2
   and t.state = 'created'

或者如果您需要所有门票的清单

SELECT t.ticket_id,t.timestamp as created, t1.timestamp as assigned, (t1.timestamp - t.timestamp) as delay
FROM table1 t
LEFT JOIN table1 t1
ON t.ticket_id = t1.ticket_id
  AND t1.state = 'assigned'
WHERE t.state = 'created'