http://manual.calibre-ebook.com/template_lang.html
in the section
Code:
format_date(x, date_format) – format_date(val, format_string) – format the value, which must be a date field, using the format_string, returning a string. The formatting codes are:
Old school DB guy here:
Why bloat the DB with 2 columns of the essentially the same data with a display variant?
If you need MMYY on an export, do it (the format conversion) in the save template
If you want the GUI to
SHOW MMYY
Preferences: Add your own column: (select your column name):click the blue i and change the
Format for dates (this is a Display format, not the data format, which is still a full date)