php - 按日期时间显示来自多个表的数据

Question

我有一个 php 页面，想显示来自多个表(目前是 3 个表)的数据
所有表格都有日期时间列
和其他列完全不同(数字和数据类型等) 我要展示
三个表中任一表的最新行
三个表中任意一个的第二行
三个表中任一表的第三行
等等

我的表结构如下

ATTANDANCE [a_id,date-time,employee,attandance_more....]   

TASKS_ASSIGN[ta_id,date-time,employee,title,detail,duration,task_assign_more.....]

TASK_COMPLETED [tc_id,date-time,employee,stars,task_completed_more....]   

我想显示为 facebook

 Alam has joined office at 23-mar-2013 **08:00am**   
 Haider has joined office at 23-mar-2013 **08:01am**  
 Alam has completed xyz-task at 22-mar-2013 **03:45pm**
 Alam has joined office at 22-mar-2013 **10:12am**
 ......

Answer 1

您似乎只需要列的子集。我不确定表格和结果之间的确切关系是什么，但类似于:

select  'attandance' as which, employee, `datetime`
from attendance
union all
select 'assign' as which, employee, `datetime`
from tasks_assign
union all
select `completed` as which, employee, `datetime`
from tasks_completed
order by `datetime` desc

也就是说，您可以使用子查询来获取每个表中列的子集。然后使用 union all 将它们组合在一起，并使用 order by 将它们按您想要的顺序排列。