检测重叠事件

Question

我有一个事件的表，用户可以输入：

event_id | title | start    | end 
----------------------------------------------------------------- 
0  | title 1 | 2014-10-29 09:00:00 | 2014-10-29 09:30:00 
1  | title 2 | 2014-10-29 09:15:00 | 2014-10-29 09:45:00 
2  | title 3 | 2014-10-29 10:00:00 | 2014-10-29 10:30:00 
2  | title 3 | 2014-10-29 11:00:00 | 2014-10-29 11:30:00 

我想如果有事件重叠在Cursor返回的附加列。

event_id | title | start    | end     | conflict 
--------------------------------------------------------------------------- 
0  | title 1 | 2014-10-29 09:00:00 | 2014-10-29 09:30:00 | 1 
1  | title 2 | 2014-10-29 09:15:00 | 2014-10-29 09:45:00 | 1 
2  | title 3 | 2014-10-29 10:00:00 | 2014-10-29 10:30:00 | 0 
2  | title 3 | 2014-10-29 11:00:00 | 2014-10-29 11:30:00 | 0 

我试图找到最好的方法来做到这一点。

Answer 1

有冲突，如果存在重叠当前事件的任何其它事件：

SELECT *, 
     EXISTS (SELECT 1 
       FROM events AS other 
       WHERE other.event_id != events.event_id 
       AND other.end > events.start 
       AND other.start < events.end) AS conflict 
FROM events