I would store 'estimatedduration' in minutes and convert to days or hours when neccessary.

>thnaks for the post sergey.
>actually i display status on front end screen.
>by the way u suggested ..

>SELECT st.assid, st.staffid,
>	(SUM(DATDIFF(minute, wt.starttime,wt.stoptime) /
>           MAX(st.estimatedduration)) * 100 AS status
>	FROM staff st
>		JOIN wortime wt ON st.assid = wt.fk_assid
>	GROUP BY assid, staffid

>but i cannot use the field (estimatedduration) directly the way u did up abv
>bcoz the values will be like 1d or 6h or 30min etc.,
>seems i need to convert estimatedduration into minutes,right ??