MySQL date type and millisecond value convert each other

Sometimes it is necessary to convert a date type value to a millisecond value, and sometimes to convert a millisecond value to a date, in order to be more convenient to meet the needs of the query.

Now, create a new database table T_stu_info and insert the data into the tables

Use Test;show tables;create table T_stu_info (     ID int. NOT NULL PRIMARY key,     stu_name varchar),     stu_date Tim Estamp,     stu_age Int (3),     stu_sex varchar (5));    Insert into T_stu_info (id,stu_name,stu_date,stu_age,stu_sex) VALUES (' 1 ', ' Zhangsan ', ' 2000-12-12 12:30:00 ', ' 15 ', ' Man '), Commit;select * from T_stu_info;

1, date converted to millisecond value

Select Unix_timestamp (t.stu_date) from T_stu_info t

2, millisecond value converted to date

SELECT     from_unixtime (Unix_timestamp (t.stu_date),            '%y-%m-%d%h:%i:%s ') as Stu_datefrom    T_stu_info t

SELECT     from_unixtime (Unix_timestamp (t.stu_date),            '%y-%m-%d ') as Stu_datefrom    T_stu_info t

MySQL date type and millisecond value convert each other