FB Date Manipulation

Last week I have a question from Delphindo (Indonesian Delphi community) thorough YM conference. The question is how to make SQL query for Firebird to obtain the same result as we do this (to_char(sysdate, 'YYMM');) in Oracle. I must admit that Firebird doesn't have this "to_char" built in function, but we can create the same result with the trick like this:

select current_date,
substring(extract(year from current_date) from 3)||
case
when char_length(extract(month from current_date))=1
then '0'||extract(month from current_date)
else
extract(month from current_date)
end as Year_Month
from rdb$database

Thank's to the new feature of Firebird 2, that can make this happen without installing any UDF. I use the "char_length" and "substring" built in function that come in Firebird 2 (version 1.5xx still not support this built in function).