mysql中多个日期范围内的月份列表

Question

I have a list of date ranges and I like to get a list of all months that are within these date ranges. I can query my date ranges like so:

Select id, start, end 
From date_range

And this query would give the following output:

1, 01-01-2016, 25-03-2016
2, 26-03-2016, 30-03-2016
3, 30-12-2016, 08-01-2017

Now I would like to find a MySQL query that just lists all months within these date ranges. So it should give the following output:

01-2016
02-2016
03-2016
12-2016
01-2017

There are already examples here on how to get a list of month between two dates, such as:

• Creating a list of month names between two dates in MySQL
• How to get a list of months between two dates in mysql

But these examples are about a single date range, but I have multiple date ranges. It would be great if someone can find an sql query for my problem.

Answer 1

Here is a solution:

#DROP TABLE IF EXISTS monthTest;
CREATE TABLE monthTest(id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY, `start` DATETIME, `end`DATETIME);

INSERT INTO monthTest(`start`, `end`) VALUES
    ('2016-01-01', '2016-03-25'),
    ('2016-03-26', '2016-03-30'),
    ('2016-12-30', '2017-08-01');

SELECT A.`start`, A.`end`, DATE_FORMAT(DATE_ADD(A.`start`, INTERVAL B.help_keyword_id MONTH), '%Y%m') FROM
    monthTest A,
    mysql.help_keyword B
WHERE PERIOD_DIFF(DATE_FORMAT(A.`end`, '%Y%m'), DATE_FORMAT(A.`start`, '%Y%m')) >= B.help_keyword_id
ORDER BY A.id;

Note that this query in the second JOIN table has a dependency that this table must contain more rows than the maximum number of months between any two dates and the join field must be an incrementing INTEGER starting from 0. This is due to the limitation that mysql doesn't (yet) contain a row generator so a workaround is necessary.

Regards,

James