MySql difference between two timestamps in days?

Answer 1

CREATE TABLE t (d1 timestamp, d2 timestamp);

INSERT INTO t VALUES ('2010-03-11 12:00:00', '2010-03-30 05:00:00');
INSERT INTO t VALUES ('2010-03-11 12:00:00', '2010-03-30 13:00:00');
INSERT INTO t VALUES ('2010-03-11 00:00:00', '2010-03-30 13:00:00');
INSERT INTO t VALUES ('2010-03-10 12:00:00', '2010-03-30 13:00:00');
INSERT INTO t VALUES ('2010-03-10 12:00:00', '2010-04-01 13:00:00');

SELECT d2, d1, DATEDIFF(d2, d1) AS diff FROM t;

+---------------------+---------------------+------+
| d2                  | d1                  | diff |
+---------------------+---------------------+------+
| 2010-03-30 05:00:00 | 2010-03-11 12:00:00 |   19 |
| 2010-03-30 13:00:00 | 2010-03-11 12:00:00 |   19 |
| 2010-03-30 13:00:00 | 2010-03-11 00:00:00 |   19 |
| 2010-03-30 13:00:00 | 2010-03-10 12:00:00 |   20 |
| 2010-04-01 13:00:00 | 2010-03-10 12:00:00 |   22 |
+---------------------+---------------------+------+
5 rows in set (0.00 sec)

Answer 2

If you're happy to ignore the time portion in the columns, DATEDIFF() will give you the difference you're looking for in days.

SELECT DATEDIFF('2010-10-08 18:23:13', '2010-09-21 21:40:36') AS days;
+------+
| days |
+------+
|   17 |
+------+