unix_timestamp()
mysql> select unix_timestamp(); +------------------+ | unix_timestamp() | +------------------+ | 1464590043 | +------------------+
unix_timestamp(date)
mysql> select unix_timestamp('2016-05-30');
+------------------------------+
| unix_timestamp('2016-05-30') |
+------------------------------+
| 1464537600 |
+------------------------------+
mysql> select unix_timestamp('2016-05-30 14:35:21');
+---------------------------------------+
| unix_timestamp('2016-05-30 14:35:21') |
+---------------------------------------+
| 1464590121 |
+---------------------------------------+
from_unixtime(unix_timestamp)
mysql> select from_unixtime(1464590043); +---------------------------+ | from_unixtime(1464590043) | +---------------------------+ | 2016-05-30 14:34:03 | +---------------------------+
from_unixtime(unix_timestamp,format)
mysql> select from_unixtime(1464590043, '%Y %D %M %h:%i:%s %x'); +---------------------------------------------------+ | from_unixtime(1464590043, '%Y %D %M %h:%i:%s %x') | +---------------------------------------------------+ | 2016 30th May 02:34:03 2016 | +---------------------------------------------------+