MYSQL Tutorial: UNIX Timestamp and date conversion function tip: UNIX timestamp to date using the function: FROM_UNIXTIME (), date to UNIX timestamp using the function: UNIX_TIMESTAMP (). function for converting UNIX timestamp to date: FROM_UNIXTIME () select FROM_UNIXTIME (1156219870); function for converting date to UNIX timestamp: UNIX_TIMESTAMP () select UNIX_TIMESTAMP ('2017-11-04 12:23:00 '); example: number of records queried by mysql on the current day: $ SQL = "select * from message Where DATE_FORMAT (FROM_UNIXTIME (chattime ), '% Y-% m-% D') = DATE_FORMAT (NOW (),' % Y-% m-% D') order by id desc "; of course, you can also choose to convert the UNIX timestamp into a date in PHP using the function: date () date ('Y-m-d H: I: s', 1156219870 ); function used to convert a date to a UNIX timestamp: strtotime () strtotime ('2017-03-24 08:15:42 ');