我知道有关重复事件的问题很常见，但除了与日历应用程序有关的重复事件之外，我还没有找到一个回答这个关于重复事件的特定问题的答案。主要区别在于我们应用程序中的事件。只会在报告中或单独出现，而不是在日历格式中，尽管在许多方面它们非常相似，可能只是与日历相关的包袱更少。
与日历应用程序类似。事件可以一次性发生，也可以重复发生，例如每个星期四或每个月的第一个星期一，直到将来某个预先设定的时间。
这些事件存储在一个事件表中，其中包含开始和结束日期以及“循环类型 ID”。如果“recurrency type”为“None”，则开始日期和结束日期将相同。事件表包含一个单独的表的 ID，该表包含事件类型名称，例如“会议”或“每周报告”
还有一个包含“循环类型”列表的表格，例如“不重复”、“每周一”、“每月的第一个星期一”和“每月的最后一个星期六”。
为了使查找更容易，另一个表包含从 1960 年到 2060 年的日期列表以及每个日期的相关信息，例如是否是星期一，以及该月中的哪个星期一。
这允许进行如下查找：
SELECT DISTINCT(e.eventid),n.nameid,n.firstname,n.lastname,d.dt,r.recurring
FROM dates d
LEFT JOIN recurringtypes r
/* if event recurring every week E.g. 'Every Monday' */
ON (r.rectypeid BETWEEN 2 AND 8 AND r.day = d.dow)
/* if event recurring every month E.g. 'First Monday, every month' */
OR ((r.rectypeid BETWEEN 9 AND 36) AND r.day = d.dow AND r.occurrence = d.occurrence)
/* if event recurring every last week of month E.g. 'Last Monday, every month' */
OR (r.rectypeid >= 37 AND r.day = d.dow and r.islast = d.islast)
LEFT JOIN events e on e.rectypeid = r.rectypeid
LEFT JOIN eventtypes t ON e.eventtypeid = t.eventtypeid
LEFT JOIN names n ON e.namesid = n.namesid
WHERE (d.dt BETWEEN '2012/02/01' AND '2012/05/01')
ORDER BY d.dt;
这正是查找重复事件所需要的，输出如下：
+-----------+---------------+-------------------+-----------+------------+-------------------------------+
| eventid | nameid | lastname | firstname | dt | recurring |
+-----------+---------------+-------------------+-----------+------------+-------------------------------+
| 3291788 | 1728449 | smith | zoe | 2012-02-02 | First Thursday, every month |
| 3291797 | 1765432 | | | 2012-02-05 | First Sunday, every month |
| 3291798 | 1730147 | | | 2012-02-05 | First Sunday, every month |
| 3291803 | 1790061 | Carpenter | Richie | 2012-02-06 | Every Monday |
| 3291805 | 1790061 | Carpenter | Richie | 2012-02-08 | Second Wednesday, every month |
| 3291803 | 1790061 | Carpenter | Richie | 2012-02-13 | Every Monday |
| 3291799 | 1790061 | Carpenter | Richie | 2012-02-15 | Third Wednesday, every month |
| 3291803 | 1790061 | Carpenter | Richie | 2012-02-20 | Every Monday |
要获得无重复事件，可以使用更简单的查询：
SELECT n.nameid,n.lastname,n.firstname,e.firstdate,e.eventid,'No' as Recurring
FROM events e
LEFT JOIN names n ON n.names = e.namesid
AND e.rectypeid <= 1
AND e.firstdate BETWEEN '2012/02/01' AND '2012/05/01'
AND e.eventid IS NOT NULL ORDER BY e.firstdate;
我的问题是：如何将这些查询组合起来，得出一个包含所有事件的列表，包括按日期顺序重复和不重复的事件？
这些是表格和它们的缩短选择，为简洁起见，一些列和所有索引已被删除:)。出于同样的原因，未包含“名称”表。
CREATE TABLE events (
eventid int(11) NOT NULL AUTO_INCREMENT,
eventtypeid int(11) DEFAULT '0',
firstdate date DEFAULT '1960-01-01' COMMENT 'First event',
lastdate date DEFAULT '1960-01-01' COMMENT 'Last event',
rectypeid int(11) DEFAULT '1'
);
+---------+-------------+------------+------------+-----------+
| eventid | eventtypeid | firstdate | lastdate | rectypeid |
+---------+-------------+------------+------------+-----------+
| 3291803 | 16 | 2012-02-03 | 2012-04-11 | 3 |
| 3291797 | 8 | 2012-02-12 | 2012-02-22 | 9 |
| 3291798 | 5 | 2012-02-12 | 2012-02-12 | 9 |
| 3291788 | 8 | 2012-05-24 | 2015-01-16 | 13 |
| 3291805 | 10 | 2012-01-04 | 2012-02-14 | 19 |
| 3291799 | 16 | 2012-02-07 | 2012-10-24 | 26 |
| 3291804 | 5 | 2012-02-03 | 2012-08-22 | 41 |
+---------+-------------+------------+------------+-----------+
CREATE TABLE cmseventtypes (
eventtypeid int(11) NOT NULL AUTO_INCREMENT,
eventtype varchar(50) DEFAULT '' COMMENT 'Event type AKA name'
);
+-------------+----------------------+
| eventtypeid | eventype |
+-------------+----------------------+
| 1 | Follow up meeting |
| 2 | Reminder email due |
| 3 | Monthly meeting |
| 4 | Weekly report |
| 5 | Golf practice |
+------------------------------------+
CREATE TABLE recurringtypes (
rectypeid int(11) NOT NULL AUTO_INCREMENT,
recurring varchar(40) DEFAULT '',
day tinyint(4) DEFAULT '0',
occurrence tinyint(4) DEFAULT '0',
islast tinyint(4) DEFAULT '0'
);
+-----------+---------------------------+------+------------+--------+
| rectypeid | recurring | day | occurrence | islast |
+-----------+---------------------------+------+------------+--------+
| 1 | No | 0 | 0 | 0 |
| 2 | Every Sunday | 1 | 0 | 0 |
| 3 | Every Monday | 2 | 0 | 0 |
| 4 | Every Tuesday | 3 | 0 | 0 |
| 5 | Every Wednesday | 4 | 0 | 0 |
| 6 | Every Thursday | 5 | 0 | 0 |
| 7 | Every Friday | 6 | 0 | 0 |
| 8 | Every Saturday | 7 | 0 | 0 |
| 9 | First Sunday, every month | 1 | 1 | 0 |
| 10 | First Monday, every month | 2 | 1 | 0 |
+-----------+---------------------------+------+------------+--------+
CREATE TABLE dates (
dt date NOT NULL COMMENT 'Date',
daycount mediumint(9) NOT NULL DEFAULT '1',
year smallint(6) NOT NULL DEFAULT '1970',
month tinyint(4) NOT NULL DEFAULT '1',
dom tinyint(4) NOT NULL DEFAULT '1',
dow tinyint(4) NOT NULL DEFAULT '1',
occurrence tinyint(4) NOT NULL DEFAULT '0',
islast tinyint(1) NOT NULL DEFAULT '0'
);
+------------+----------+------+-------+-----+-----+------------+--------+
| dt | daycount | year | month | dom | dow | occurrence | islast |
+------------+----------+------+-------+-----+-----+------------+--------+
| 2012-02-02 | 734900 | 2012 | 2 | 2 | 5 | 1 | 0 |
| 2012-02-03 | 734901 | 2012 | 2 | 3 | 6 | 1 | 0 |
| 2012-02-04 | 734902 | 2012 | 2 | 4 | 7 | 1 | 0 |
| 2012-02-05 | 734903 | 2012 | 2 | 5 | 1 | 1 | 0 |
| 2012-02-06 | 734904 | 2012 | 2 | 6 | 2 | 1 | 0 |
| 2012-02-07 | 734905 | 2012 | 2 | 7 | 3 | 1 | 0 |
| 2012-02-08 | 734906 | 2012 | 2 | 8 | 4 | 2 | 0 |
| 2012-02-09 | 734907 | 2012 | 2 | 9 | 5 | 2 | 0 |
+------------+----------+------+-------+-----+-----+------------+--------+
我们并非绝对使用上述代码或表格布局，欢迎任何可行的解决方案。请不要将我指向：
在构建日历应用程序时，我应该在我的数据库中存储日期或重复规则吗？
或者
https://www.rfc-editor.org/rfc/rfc5545
我已经检查了它们，它们非常有用，但没有像我们预期的那样做。
TIA