MySQL 8.0

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CREATE TABLE your_table (id INT PRIMARY KEY, date_col VARCHAR(20) NOT NULL);
INSERT INTO your_table VALUES
  (1, 'September 29, 2012'),
  (2, 'April 9, 2013'),
  (3, 'March 3, 2015'),
  (4, 'December 19, 2012');

SELECT * FROM your_table;

Records: 4  Duplicates: 0  Warnings: 0




id
date_col


1
September 29, 2012

2
April 9, 2013

3
March 3, 2015

4
December 19, 2012


SELECT * FROM your_table ORDER BY date_col ASC;


id
date_col


2
April 9, 2013

4
December 19, 2012

3
March 3, 2015

1
September 29, 2012


UPDATE your_table SET date_col = STR_TO_DATE(date_col, '%M %e, %Y');
ALTER TABLE your_table MODIFY COLUMN date_col DATE NOT NULL;

Rows matched: 4  Changed: 4  Warnings: 0



Records: 4  Duplicates: 0  Warnings: 0


SELECT id, date_col, DATE_FORMAT(date_col, '%d-%m-%Y') AS dt
FROM your_table
ORDER BY date_col ASC;


id
date_col
dt


1
2012-09-29
29-09-2012

4
2012-12-19
19-12-2012

2
2013-04-09
09-04-2013

3
2015-03-03
03-03-2015

id	date_col
1	September 29, 2012
2	April 9, 2013
3	March 3, 2015
4	December 19, 2012

id	date_col	dt
1	2012-09-29	29-09-2012
4	2012-12-19	19-12-2012
2	2013-04-09	09-04-2013
3	2015-03-03	03-03-2015