日期范围的总和，不计算MySQL中的重叠

本文介绍了日期范围的总和，不计算MySQL中的重叠的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我有一个简单的表，其中有start_date和end_date列.这些日期值可能会重叠

I have simple table with start_date and end_date columns in it. These date values may overlap

id start_date end_date 1 2011-01-01 2012-04-01 2 2012-05-01 2013-10-01 3 2013-09-01 2014-09-01 4 2013-10-01 2014-08-01 5 2013-12-01 2014-11-01 6 2013-09-01 2014-09-01 7 2015-01-01 2015-11-01

问题是要在几个月内找到总和.例子: id: 2,3,4,5,6重叠，所以想法是取2,3,4,5,6的MAX end_date和MIN start_date并加上1和7的日期差.

Problem is to find sum in months. Example: id: 2,3,4,5,6 overlap so idea is to take MAX end_date and MIN start_date of 2,3,4,5,6 and add date difference of 1, and of 7.

这时:我已经找到了如何估算月份中的日期差异:

At this time: I've found how to estimate date difference in months:

PERIOD_DIFF( DATE_FORMAT(end_date, '%Y%m') , DATE_FORMAT(start_date, '%Y%m') )

我知道这里的想法是:

了解两个日期是否重叠.如果是，则相应地合并日期(如果需要，请调整结束日期和开始日期)

遍历所有日期，估计以月为单位的日期差，求和并返回最终结果.

我一直在寻找类似的问题，但无法解决和提出问题，如果您能帮助我，那将是很好的.我知道可以使用某种编程语言并在那里进行估算，但想使用MySQL查询编写它.

I've been looking for similar questions and couldn't resolve and issue, would be nice if you could help me. I know it is possible to do using some programming language and estimate it there, but wanted to write it using MySQL query.

谢谢

推荐答案

这很忙，但应该可以满足您的需求:

This is hectic as anything but should get you what you need:

SELECT SUM(PERIOD_DIFF(EXTRACT(YEAR_MONTH FROM a.end_date), EXTRACT(YEAR_MONTH FROM a.start_date))) months FROM ( SELECT MIN(g.start_date) start_date, MAX(g.end_date) end_date FROM ( SELECT @group_id := @group_id + (@end_date IS NULL OR o.start_date > @end_date) group_id, start_date, @end_date := DATE(CASE WHEN (@end_date IS NULL OR o.start_date > @end_date) THEN o.end_date ELSE GREATEST(o.end_date, @end_date) END) end_date FROM overlap o JOIN (SELECT @group_id := 0, @end_date := NULL) init ORDER BY o.start_date ASC ) g GROUP BY g.group_id ) a

最里面的查询在适当的情况下将您的时间段分成重叠的组，并延长了end_date.我认为end_date会弯曲，因为我认为前者可能完全封闭了一段时间.

The inner-most query groups together your periods in overlapping groups stretching the end_date where appropriate. The end_date flexes as I assumed that there could be periods completely enclosed by the previous.

下一个换行查询从每个组中提取全部范围.

The next wrapping query extracts the full range from each group.

外部查询汇总每个组的整月差异.所有组差异均通过PERIOD_DIFF向下舍入到最接近的完整月份.

The outer query sums up the full month diffs for each group. All group diffs are rounded down to the nearest full month by PERIOD_DIFF.

不幸的是，由于SQLFiddle对我死亡，我无法对此进行测试.

Unfortunately I couldn't test this as SQLFiddle has died on me.