Conversion of date and long type in MySQL database

1. In the MySQL database, "00:00:00" is converted to a long integer function:

Select unix_timstamp ("00:00:00") * 1000, </P> <p>

Note that the long integer in the MySQL database is less than the number of milliseconds after the second than the long integer in Java, so it is multiplied by 1000, so the difference is only a few milliseconds.

2. in MySQL databases, "1252999488000" (long data in Java) is converted to a date:

Select from_unixtime (1252999488); </P> <p>

Note: remove the last three digits.