Difference between two datetime entries

Question

SELECT ETA,STA FROM `Schedule` WHERE `Num`="5567";

2013-08-26 18:37:00 2013-08-26 18:30:00

SELECT DATEDIFF(ETA,STA) FROM `Schedule` WHERE `Num`="5567";

0

Why the result is 0 instead of 7 (i.e. minutes)?

Answer 1

DATEDIFF will give result in days.

SELECT HOUR (ETA - STA) FROM `Schedule` WHERE `Num`="5567";

An alternative for hour difference.

Answer 2

You can do this using TIME_TO_SEC MySQL function.

Sample

SELECT (TIME_TO_SEC(ETA) - TIME_TO_SEC(STA))/60 AS `minutes` 

Answer 3

Use TIMEDIFF function

SELECT TIMEDIFF(ETA,STA) FROM `Schedule` WHERE `Num`="5567";

Answer 4

Refer to this thread on how to calculate the difference in munites: Calculating time difference between 2 dates in minutes

DATEDIFF will return the difference in days!

From the docs: DATEDIFF() returns expr1 – expr2 expressed as a value in days from one date to the other. expr1 and expr2 are date or date-and-time expressions. Only the date parts of the values are used in the calculation.

mysql> SELECT DATEDIFF('2007-12-31 23:59:59','2007-12-30');
    -> 1

Answer 5

SELECT (TIMEDIFF(ETA,STA)) FROM SCHEDULE will give it in formatted minutes and return 00:07:00

SELECT TIME_TO_MIN(TIMEDIFF(ETA,STA)) FROM SCHEDULE gives 420

(7 * 60 seconds = 420)