How to get date increments in between start date and end date in MYSQL

Question

I have sample dates in a table and what I need to get is each of the months between the start date and end date.

sample :

 ID   Startdate    EndDate
 1   01-01-2019  01-03-2019
 2   01-08-2019  01-02-2020

I need to fetch months and year from these dates.

Desired output :

ID  Dates
1  January 2019
1  February 2019
1  March 2019
2  August 2019
2  September 2019
2  October 2019
2  November 2019
2  December 2019
2  January 2020
2  February 2020 

How cah I achieve this in MySQL and how to do increment or any loop kind of operation. On the query side I'm not getting any idea to move on this.

Answer 1

Here are a couple of ways to achieve this. The first will only work on MySQL 8+ and uses a recursive CTE to generate the months between StartDate and EndDate :

WITH RECURSIVE CTE AS (
  SELECT ID, Startdate AS d, EndDate
  FROM dates
  UNION ALL
  SELECT ID, d + INTERVAL 1 MONTH, EndDate
  FROM CTE
  WHERE d < EndDate
)
SELECT ID, DATE_FORMAT(d, '%M %Y') AS Dates
FROM CTE
ORDER BY ID, d

The second (which will run on any version of MySQL) uses a numbers table (in this case numbers from 0 to 99, allowing for a range of up to 99 months between StartDate and EndDate ; if you need longer, adding more tables to the CROSS JOIN will increase that range by a factor of 10 for each table added) to generate the list of months difference, this is then JOIN ed to the original table so that the generated date Startdate + INTERVAL nn MONTH is less than or equal to EndDate :

SELECT ID, DATE_FORMAT(Startdate + INTERVAL n.n MONTH, '%M %Y') AS Dates
FROM dates
JOIN (
  SELECT n10.n * 10 + n1.n * 1 AS n
  FROM (
    SELECT 0 n UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3
    UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6
    UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9
  ) n10
  CROSS JOIN (
    SELECT 0 n UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3
    UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6
    UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9
  ) n1
) n ON Startdate + INTERVAL n.n MONTH <= EndDate
ORDER BY ID, Startdate + INTERVAL n.n MONTH

Having generated our list of dates, we format it using DATE_FORMAT and a format string of %M %Y . For both queries the output is:

ID  Dates
1   January 2019
1   February 2019
1   March 2019
2   August 2019
2   September 2019
2   October 2019
2   November 2019
2   December 2019
2   January 2020
2   February 2020

Demo on dbfiddle