Seconds Since the Beginning of the Day : Introduction « Date Time Functions « MySQL Tutorial

TIME_TO_SEC(time) returns the time in seconds (the number of seconds since the beginning of that day).

SEC_TO_TIME(seconds) does the opposite, converting the number of seconds from the beginning of the day into HH:MM:SS or HHMMSS format.

mysql>
mysql> select TIME_TO_SEC('01.00.00');
+-------------------------+
| TIME_TO_SEC('01.00.00') |
+-------------------------+
|                       1 |
+-------------------------+
1 row in set, 1 warning (0.00 sec)

mysql>
mysql> SELECT TIME_TO_SEC(110);
+------------------+
| TIME_TO_SEC(110) |
+------------------+
|               70 |
+------------------+
1 row in set (0.00 sec)

mysql>
mysql> SELECT SEC_TO_TIME(70);
+-----------------+
| SEC_TO_TIME(70) |
+-----------------+
| 00:01:10        |
+-----------------+
1 row in set (0.00 sec)

mysql>
mysql> SELECT SEC_TO_TIME(1000)+0;
+---------------------+
| SEC_TO_TIME(1000)+0 |
+---------------------+
|         1640.000000 |
+---------------------+
1 row in set (0.02 sec)

mysql>

14.1.Introduction
	14.1.1.	Date and Time Functions
	14.1.2.	Extraction Functions
	14.1.3.	Changing Date Values
	14.1.4.	Getting Day Information
	14.1.5.	Getting Names for Months and Days
	14.1.6.	Extracting Years, Quarters, Months, and Weeks
	14.1.7.	Current Date and Time
	14.1.8.	Days Since 1 A.D.
	14.1.9.	Seconds Since the Beginning of the Day