[Oracle] simple date and time formatting and sorting problem

The so-called format date refers to converting the date into a string , Or convert the string to a date , The following functions can be used to format dates .

TO_CHAR(datetime, 'format')
TO_DATE(character, 'format')
TO_TIMESTAMP(character, 'format')
TO_TIMESTAMP_TZ(character, 'format')

Example

select to_char(a.CREATE_TIME,'yyyy-mm-dd')  from students

select * from Table name where Conditions can be added to this ORDER BY Date fields desc, The time field desc
This is to write a ORDER BY Keywords are sorted according to the date field, then add a comma, and then write the time field to sort

select to_char(a.CREATE_TIME,'yyyy-mm-dd')  from students 
where a.s_name like '% yellow ' order by a.create_time

Oracle Format date
oracle Database about sorting by date and time