Hello

In mysql I use a function called date_sub that substract X days from a
date.
I can also use a function called Now() that returns the current
date/time.
These two functions I use in a sqlquery, here is the interesting part:

[...] WHERE from_date > DATE_SUB(now(), interval 2 day) [...]

that gives me all entries written from 2 days ago to present time.
Are there any UDFs availible that I can use in a similar query for
firebird?

Where can I find docs about all UDF's that are availible?

Thanks,
Jonas