比较mysql表中的最新日期和最早日期，仅显示更改

Question

我有一个名为archive的表：

| staff_id |   longname  | username | projectNo |  title   | process | creation_time |
|    01    |   John Doe  |   John   |    1701   | project1 | ANM(ld) |  2017-01-16   |
|    02    | Aaron Jones |   Aaron  |    1701   | project1 | ANM(ch) |  2017-01-16   |
|    03    | James Bond  |   James  |    1702   | project2 | BGD(ld) |  2017-01-16   |
|    01    |   John Doe  |   John   |    1702   | project2 | CGI(ld) |  2017-01-16   |
|    01    |   John Doe  |   John   |    1701   | project1 | ANM(ld) |  2017-03-16   |
|    02    | Aaron Jones |   Aaron  |    1701   | project1 | BGD(ch) |  2017-03-16   |
|    03    | James Bond  |   James  |    1702   | project2 | BGD(ld) |  2017-03-16   |
|    01    |   John Doe  |   John   |    1702   | project2 | CGI(ld) |  2017-03-16   |

我想选择最新日期和最早日期，然后比较这两个查询并仅显示已更改的行。所以从上面的表格中可以看出：

| staff_id |   longname  | username | projectNo |  title   | process | creation_time |
|    02    | Aaron Jones |   Aaron  |    1701   | project1 | BGD(ch) |  2017-03-16   |

因为只有这一行被改变了。

我知道如何在查询中选择最早的日期：

SELECT staff_id, longname, username, title, process, creation_time FROM archived
WHERE creation_time IN (SELECT min(creation_time) FROM archived)

最新日期：

SELECT staff_id, longname, username, title, process, creation_time FROM archived
WHERE creation_time IN (SELECT max(creation_time) FROM archived)

问题是如何比较查询并仅显示更改？

修改

好的，我所拥有的是表存档：

| staff_id |   longname  | username | projectNo |  title   | process | creation_time |
|    01    |   John Doe  |   John   |    1701   | project1 | ANM(ld) |  2017-01-16   |
|    02    | Aaron Jones |   Aaron  |    1701   | project1 | ANM(ch) |  2017-01-16   |
|    03    | James Bond  |   James  |    1702   | project2 | BGD(ld) |  2017-01-16   |
|    01    |   John Doe  |   John   |    1702   | project2 | CGI(ld) |  2017-01-16   |
|    01    |   John Doe  |   John   |    1701   | project1 | ANM(ld) |  2017-03-16   |
|    02    | Aaron Jones |   Aaron  |    1701   | project1 | BGD(ch) |  2017-03-16   |
|    03    | James Bond  |   James  |    1702   | project2 | BGD(ld) |  2017-03-16   |
|    01    |   John Doe  |   John   |    1702   | project2 | CGI(ld) |  2017-03-16   |

表格每天00:00:00更新。所以最新的一天会有所不同。我想要的是带第一个日期的行：

|    01    |   John Doe  |   John   |    1701   | project1 | ANM(ld) |  2017-01-16   |
|    02    | Aaron Jones |   Aaron  |    1701   | project1 | ANM(ch) |  2017-01-16   |
|    03    | James Bond  |   James  |    1702   | project2 | BGD(ld) |  2017-01-16   |
|    01    |   John Doe  |   John   |    1702   | project2 | CGI(ld) |  2017-01-16   | 

最新日期：

|    01    |   John Doe  |   John   |    1701   | project1 | ANM(ld) |  2017-03-16   |
|    02    | Aaron Jones |   Aaron  |    1701   | project1 | BGD(ch) |  2017-03-16   |
|    03    | James Bond  |   James  |    1702   | project2 | BGD(ld) |  2017-03-16   |
|    01    |   John Doe  |   John   |    1702   | project2 | CGI(ld) |  2017-03-16   |

然后逐行比较。例如：

|    01    |   John Doe  |   John   |    1701   | project1 | ANM(ld) |  2017-01-16   |

与

|    01    |   John Doe  |   John   |    1701   | project1 | ANM(ld) |  2017-03-16   |

行是一样的，所以我不需要将它们显示为

|    01    |   John Doe  |   John   |    1702   | project2 | CGI(ld) |  2017-01-16   |

与

|    01    |   John Doe  |   John   |    1702   | project2 | CGI(ld) |  2017-03-16   |

这些行也一样。所以我想要打印的唯一行是

| staff_id |   longname  | username | projectNo |  title   | process | creation_time |
|    02    | Aaron Jones |   Aaron  |    1701   | project1 | BGD(ch) |  2017-03-16   |

因为它与众不同。

Answer 1

试试这个：

select tmax.*
from yourtable tmax
inner join (
    select staff_id, max(`creation_time`) as maxtime, min(`creation_time`) as mintime
    from yourtable
    group by staff_id
) t on tmax.staff_id = t.staff_id and tmax.creation_time = t.maxtime
inner join yourtable tmin
on t.staff_id = tmin.staff_id and tmin.creation_time = t.mintime
where tmax.projectNo <> tmin.projectNo or tmax.title <> tmin.title or tmax.`process` <> tmin.`process`

请在此处查看sqlfiddle demo。

子查询将获取每个staff_id的最大时间和最小时间，然后使用staff_id和最大，最小时间两次加入您的表，其中statement是您的标准。