SQL到'；集团'；某些记录

我不完全确定这在SQL中是否可行（我绝不是专家）

我在表A中有如下数据行：

我希望有一个SQL输出，将所有记录“分组”在一起，在哪里活动=D.输出结果需要如下表所示：

任何“合并”活动都将被分组为“合并”。在本例中，这将是A和B

我开始了

select 
  cycle_start,
  cycle_end,
  activity_start,
  activity_end,
  case when (Activity="D") then "D" else "Merged" end

---

但是我很难获得正确的聚合

是的，您可以通过

组中的
案例
来实现这一点：

select cycle_start, cycle_end,
       min(activity_start) as activity_start, 
       max(activity_end) as activity_end, 
       (case when Activity = 'D' then 'D' else 'Merged' end)
from table t
group by cycle_start, cycle_end,
         (case when Activity = 'D' then 'D' else 'Merged' end)

是的，您可以通过
分组方式中的
案例
执行此操作：

select cycle_start, cycle_end,
       min(activity_start) as activity_start, 
       max(activity_end) as activity_end, 
       (case when Activity = 'D' then 'D' else 'Merged' end)
from table t
group by cycle_start, cycle_end,
         (case when Activity = 'D' then 'D' else 'Merged' end)

是的，您可以通过
分组方式中的
案例
执行此操作：

select cycle_start, cycle_end,
       min(activity_start) as activity_start, 
       max(activity_end) as activity_end, 
       (case when Activity = 'D' then 'D' else 'Merged' end)
from table t
group by cycle_start, cycle_end,
         (case when Activity = 'D' then 'D' else 'Merged' end)

是的，您可以通过
分组方式中的
案例
执行此操作：

select cycle_start, cycle_end,
       min(activity_start) as activity_start, 
       max(activity_end) as activity_end, 
       (case when Activity = 'D' then 'D' else 'Merged' end)
from table t
group by cycle_start, cycle_end,
         (case when Activity = 'D' then 'D' else 'Merged' end)

@用户2407394。谢谢。@user2407394。谢谢。@user2407394。谢谢。@user2407394。非常感谢。