Hi sugi,
add your delta value to '00:00' to convert to time format.

Ali

--- In firebird-support@yahoogroups.com, sugi <truesaint@c...> wrote:
> Dear all,
>
> I found out the hard way tonight that the following stored
procedure
> code doesn't work... Firebird 1.5.2, Win32, Dialect 3 database.
>
> ...
> declare variable begin_time time;
> declare variable end_time time;
> declare variable delta time;
> ...
> //calculate delta after fetching begin_time and end_time
> delta = end_time - begin_time;
> ...
>
> The calculation seem to fail everytime with the following error
message:
> "Overflow occured during data type conversion. Conversion error
from
> string "3000.0000"."
>
> After some fiddling, it seems that the result of the (end_time -
> begin_time) expression is processed as a numeric data. Changing
the
> delta variable into an integer solves the issue, partially...
>
> ...
> declare variable delta integer;
> ...
> delta = end_time - begin_time;
> ...
>
> But now the delta variable holds an INTEGER containing elapsed
time in
> SECONDS, while I need this to be a TIME or TIMESTAMP format...
Manually
> casting it back to TIME data fails with the same error message as
above.
> Am i missing something here?
>
> The funny thing is that I recall writing some similar code in the
past,
> but i don't remember having *any* problems like this.
>
> Thanks in advance,
> sugi.