Hi,
You could change you calculation thus:
CAST(EXTRACT(HOUR,[TIMEDIFF]),VARCHAR(2))||':'||
CAST(EXTRACT(MINUTE,[TIMEDIFF]),VARCHAR(2))||':'||
CAST(FLOOR(EXTRACT(SECOND,[TIMEDIFF])),VARCHAR(2))
Alternatively, for better efficiency, you could do the following:
Create a calculation for each time part
EXTRACT(HOUR,[TIMEDIFF]) - call this HR
EXTRACT(MINUTE,[TIMEDIFF]) - call this MT
FLOOR(EXTRACT(SECOND,[TIMEDIFF])) - call this SC
In Report Studio, press the padlock button (unlock) to unlock the structure of your list.
Drag the MT and SC calculations into the same column as HR, then from the toolbox drag a text item between
and [MT] and type a colon (

. Do the same between [MT] and [SC].
Press the padlock button again to relock, and you're all done - you should now have a displayed column in the format Hours:Minutes:Seconds, but with no data type translations required, improving efficiency.
Hope that helps,
MF.