String to date

1. String to date type

delete from  EA_ATTENDANCE_TIME a where a.eat_workdate = to_date('2016-02-22','yyyy-mm-dd') and a.eat_employeeid='990207400000';

2. Date to string type

select * from  EA_ATTENDANCE_TIME a where to_char(a.eat_workdate,'YYYY-mm-dd') = '2016-03-08';

3. Every now and then

select to_date('2005-01-01 13:14:20','yyyy-MM-dd HH24:mi:ss') from dual;