--- In firebird-support@yahoogroups.com, Helen Borrie <helebor@...> wrote:

> At 11:39 AM 28/09/2010, Robert martin wrote:
> >How to I add minutes to a TimeStamp?
>
> Don't be tempted to use (5/1440) - that expression results in zero!
>
> For 5 mins this expression should get you near enough:
> aTimestamp + (5.00000000/1440)
>
> ./heLen
>

Or use the DATEADD function:
http://www.firebirdsql.org/refdocs/langrefupd21-intfunc-dateadd.html
from the sample provided:
select dateadd (minute, 5, time 'now')
from rdb$database;