Best way to get current year minus 5 years
There are different ways to achieve the goal.
SQL&gt; select to_char(trunc(add_months(sysdate,-12*5),'YEAR'),'YYYYMM') from dual;

OR
SQL&gt;  select to_char(trunc(SYSDATE - interval '5' year,'YEAR'),'YYYYMM') from dual;

Regarding the second one, what happens if the SYSDATE or the current date supplied happens to be a leap day?
SQL&gt; select to_char(trunc(to_Date('2016-02-29','YYYY-MM-DD') - interval '5' year,'YEAR'),'YYYYMM') 
    from dual;
select to_char(trunc(to_Date('2016-02-29','YYYY-MM-DD') - interval '5' year,'YEAR'),'YYYYMM') 
from dual
                                                        *
ERROR at line 1:
ORA-01839: date not valid for month specified

What happens if we use the first method?
SQL&gt; select to_char(trunc(add_months(to_Date('2016-02-29','YYYY-MM-DD'),-12*5),'YEAR'),'YYYYMM') 
     from dual;

TO_CHA
------
201101