Subtract two dates stored as varchar I have 2 varchars like:

20160316131824
20160316080002


How can I subtract to see if there is more than 24 hours of difference between the 2 values?

I tried using the symbol - but it gives me an error. What is the best way?
Here is the sample query to convert the given varchar2 value to date and calculated the difference in hour.

select (to_date('20160316124052', 'yyyy-mm-dd hh24:mi:ss')-to_date('20160316080002', 'yyyy-mm-dd hh24:mi:ss'))*24 DateAndTime from dual;


Update

SELECT (sysdate-to_date(START_TIME,'YYYYMMDDHH24MISS'))*24 FROM LOGGING WHERE NAME='TERR_PAST' AND UPPER(STATUS) = 'EXECUTED';