Increased column value in one row - mysql

Question

I have the following stored procedure get the last 12 months from the current date in MySql
DELIMITER $$
CREATE
PROCEDURE `Calendar`()
BEGIN
CREATE TEMPORARY TABLE IF NOT EXISTS `Cal` (
`month` INT(11) ,
`year` INT(11)
);
TRUNCATE TABLE Cal;
SET #counter := -1;
WHILE (DATEDIFF(DATE(NOW()), DATE(DATE_SUB(NOW(),INTERVAL #counter MONTH))) < DATEDIFF(DATE(NOW()), DATE(DATE_SUB(NOW(),INTERVAL 12 MONTH)))) DO
INSERT INTO Cal SELECT DATE_FORMAT(DATE_ADD(DATE_SUB(NOW(),INTERVAL 12 MONTH), INTERVAL #counter:=#counter + 1 MONTH),'%m'),DATE_FORMAT(DATE_ADD(DATE_SUB(NOW(),INTERVAL 12 MONTH), INTERVAL #counter + 1 MONTH),'%Y');
END WHILE;
SELECT * FROM `Cal`;
END$$
DELIMITER ;
DROP PROCEDURE IF EXISTS Calendar;
The output table is
9 2017
10 2017
11 2017
12 2018
1 2018
2 2018
3 2018
4 2018
5 2018
6 2018
7 2018
8 2018
9 2018
In the month 12, the year is 2018. It should be 2017 and also the row 9 2017 shouldn't be there since its the 13th month including the current month. How can I make the 12th month's year to 2017 and remove the 9 2017 Thanks in advance

Answer 1

Here's a stored procedure that will give you the output you desire. It's longer but simpler than what you were attempting.
DELIMITER //
DROP PROCEDURE IF EXISTS Calendar //
CREATE PROCEDURE Calendar ()
BEGIN
DECLARE month INT DEFAULT MONTH(CURDATE());
DECLARE year INT DEFAULT YEAR(CURDATE()) - 1;
CREATE TEMPORARY TABLE CAL (month INT, year INT);
REPEAT
SET month = month + 1;
IF (month = 13) THEN
SET month = 1;
SET year = year + 1;
END IF;
INSERT INTO CAL VALUES (month, year);
UNTIL month = MONTH(CURDATE())
END REPEAT;
SELECT * FROM CAL;
DROP TABLE CAL;
END //
DELIMITER ;
CALL Calendar();
Output:
month year
10 2017
11 2017
12 2017
1 2018
2 2018
3 2018
4 2018
5 2018
6 2018
7 2018
8 2018
9 2018

Answer 2

You can also do it without a creating a stored procedure, temporary table, inserting into temporary table and dropping the stored procedure after
By using a number generator in MySQL code.
Query
SELECT
MONTH(NOW() - INTERVAL number_generator.number MONTH) AS `month`
, YEAR(NOW() - INTERVAL number_generator.number MONTH) AS `year`
FROM (
SELECT
(#NUMBER := #NUMBER + 1) AS number
FROM (
SELECT 1 AS number UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10
) AS records_1
CROSS JOIN (
SELECT 1 AS number UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10
) AS records_2
CROSS JOIN (SELECT #NUMBER := 0) AS init_user_params
) AS number_generator
WHERE
number_generator.number BETWEEN 1 AND 12
AND
MONTH(NOW()) <> MONTH(NOW() - INTERVAL number_generator.number MONTH)
ORDER BY
YEAR(NOW() - INTERVAL number_generator.number MONTH) ASC
, MONTH(NOW() - INTERVAL number_generator.number MONTH) ASC
Results
| month | year |
|-------|------|
| 10 | 2017 |
| 11 | 2017 |
| 12 | 2017 |
| 1 | 2018 |
| 2 | 2018 |
| 3 | 2018 |
| 4 | 2018 |
| 5 | 2018 |
| 6 | 2018 |
| 7 | 2018 |
| 8 | 2018 |
see demo http://sqlfiddle.com/#!9/340e01/584
Note if you use MySQL 8.0+ the syntax is more clear using common table expressions.
Query
WITH RECURSIVE number_generator (number) AS
(
SELECT 1 AS number
UNION ALL
SELECT number + 1 FROM number_generator WHERE number < 12
)
SELECT
MONTH(NOW() - INTERVAL number_generator.number MONTH) AS `month`
, YEAR(NOW() - INTERVAL number_generator.number MONTH) AS `year`
FROM
number_generator
WHERE
MONTH(NOW()) <> MONTH(NOW() - INTERVAL number_generator.number MONTH)
ORDER BY
YEAR(NOW() - INTERVAL number_generator.number MONTH) ASC
, MONTH(NOW() - INTERVAL number_generator.number MONTH) ASC
Results
| month | year |
|-------|------|
| 10 | 2017 |
| 11 | 2017 |
| 12 | 2017 |
| 1 | 2018 |
| 2 | 2018 |
| 3 | 2018 |
| 4 | 2018 |
| 5 | 2018 |
| 6 | 2018 |
| 7 | 2018 |
| 8 | 2018 |
see demo https://www.db-fiddle.com/f/chJ4qS2ocXS79vGkFBg7PR/13