Oracle's solution: to_date (), 24-hour notation, and display of MM minutes

Oracle's solution is to_date () and 24-hour notation and the display of MM minutes:
1. When Oracle's to_date function is used for date conversion, many Program Like me, the engineer may intuitively convert the format "yyyy-mm-dd hh: mm: SS", but it may cause an error in Oracle: "ora 01810 format Code Appears twice ".

For example:Select to_date ('1970-01-01 13:14:20 ', 'yyyy-mm-dd hh24: mm: ss') from dual;

The reason is that SQL statements are case-insensitive. mm and mm are considered to be the same format code, so Oracle SQL uses Mi instead of minutes.

Select To_date ( ' 13:14:20 ' , ' Yyyy-mm-dd hh24: MI: SS ' ) From Dual;

second, it must be displayed in the form of 24 hours with hh24 select to_char (sysdate, ' yyyy-mm-dd hh24: MI: SS ' ) from dual; // Mi is a minute
select to_char (sysdate, ' yyyy-mm-dd hh24: mm: SS ' ) from dual; // MM displays the month