I'm wanting to select items that have a timestamp value that's a certain
number of minutes from current_timestamp. E.g., to select items that
have some_date within the last 10 minutes, I'm trying something like:

select * from foo where some_date - (10.0/(24.0*60.0)) >=
current_timestamp

This is based on the documentation that says the decimal portion of a
number is added as minutes to the timestamp value.

Apart from this being a very awkward way to express an interval, there
are rounding errors -- e.g. the expression of 10 minutes above appears
to behave more like 9 minutes.

Is there a better way to handle this?

-- Garrett