Maintenance Task status of SCCM
So many maintenance task running at SCCM server, to figure it out, you need a query to your SCCM Database, here you go:
select *,
floor(DATEDIFF(ss,laststarttime,lastcompletiontime)/3600) as Hours,
floor(DATEDIFF(ss,laststarttime,lastcompletiontime)/60)- floor(DATEDIFF(ss,laststarttime,lastcompletiontime)/3600)*60 as Minutes,
floor(DATEDIFF(ss,laststarttime,lastcompletiontime))- floor(DATEDIFF(ss,laststarttime,lastcompletiontime)/60)*60 as TotalSeconds
from SQLTaskStatus
the result just like this, neat isn’t it 
taken the source from: http://anoopmannur.wordpress.com/2010/12/06/reporting-of-maintenance-tasks-status-of-sccm-primary-server/