How Can I Create a DATE Object in MySQL from Separate Day, Month, and Year Fields?

Create a Date Object from Day, Month, and Year Fields in MySQL

In a database schema with a 'date' table containing separate fields for 'day,' 'month,' and 'year,' it becomes necessary to create a date object for comparisons. This article outlines a solution for constructing a date object from these integer values.

Using the MAKEDATE() and DATE_ADD() functions, a DATETIME can be created from the year, month, and day components. MAKEDATE() generates a DATETIME representing the first day of the specified year. Subsequently, DATE_ADD() can be applied to add the month and day values.

For instance:

SELECT MAKEDATE(2013, 1);
+-------------------+
| MAKEDATE(2013, 1) |
+-------------------+
| 2013-01-01        |
+-------------------+

To incorporate the month and day values:

SELECT DATE_ADD(MAKEDATE(2013, 1), INTERVAL (3)-1 MONTH);
+---------------------------------------------------+
| DATE_ADD(MAKEDATE(2013, 1), INTERVAL (3)-1 MONTH) |
+---------------------------------------------------+
| 2013-03-01                                        |
+---------------------------------------------------+

Combining multiple DATE_ADD() calls allows for precise date construction:

SELECT DATE_ADD(DATE_ADD(MAKEDATE(2013, 1), INTERVAL (3)-1 MONTH), INTERVAL (11)-1 DAY);
| DATE_ADD(DATE_ADD(MAKEDATE(2013, 1), INTERVAL (3)-1 MONTH), INTERVAL (11)-1 DAY) |
+----------------------------------------------------------------------------------+
| 2013-03-11                                                                       |
+----------------------------------------------------------------------------------+

To execute a date range query using this technique:

SELECT * FROM `date`
WHERE DATE_ADD(DATE_ADD(MAKEDATE(year, 1), INTERVAL (month)-1 MONTH), INTERVAL (day)-1 DAY)
BETWEEN '2013-01-01' AND '2014-01-01';

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