找出mysql中两个日期范围之间重叠的天数

Question

I have a table with a date range. I would like to find out if it overlaps another range and calculate the number of days overlapped.

Trying to do it in just mysql without going through loops in PHP which is the front end language.

id | start_date | end_date
1  | 2019-01-02 | 2019-01-07
2  | 2019-01-03 | 2019-01-03
3  | 2019-01-06 | 2019-01-09

Date Range start = 2019-01-04 , Date range end = 2019-01-07

With the dates being in the format YYYY-MM-DD

Would like the end result being :

id | start_date | end_date    | total_days
1  | 2019-01-02 | 2019-01-07  | 4
2  | 2019-01-03 | 2019-01-03  | 0
3  | 2019-01-05 | 2019-01-09  | 3

Answer 1

Try to use MySQL DATEDIFF() function:

MySQL DATEDIFF() returns the number of days between two dates or datetimes. This function only calculates the date portion from each expression.

DATEDIFF(expr1,expr2);

Click here to find examples