I thought we'd fixed this ...
regression=# select to_char('2009-01-01'::date, 'YY');
to_char
---------
09
(1 row)
regression=# select to_char('2009-01-01'::date, 'FMYY');
to_char
---------
09
(1 row)
Not a lot of zero suppression happening there :-(.
I believe the correct fix is to reduce the year mod 100 (or 10 or 1000)
before feeding it to snprintf, rather than playing games with printing
only part of the result string as the original and current code try to
do.
regards, tom lane