Sum the Lock Time from two tables

Hi All,
DECLARE
@Lock TABLE(LogInID INT, UserName VARCHAR(50), IpAddress VARCHAR(50), LogInDate DATETIME)INSERT
INTO @LockSELECT
10, 'rkbabu', '111.111.111.111', 'Aug 24 2010 1:05AM' UNION ALLSELECT
10, 'rkbabu', '111.111.111.111', 'Aug 24 2010 2:00AM' UNION ALLSELECT
10, 'rkbabu', '111.111.111.111', 'Aug 24 2010 2:14AM' UNION ALLSELECT
10, 'rkbabu', '111.111.111.111', 'Aug 24 2010 3:02AM' UNION ALLSELECT 11, 'rkbabu', '111.111.111.111', 'Aug 24 2010 11:38PM' DECLARE
@UnLock TABLE(LogInID INT, UserName VARCHAR(50), IpAddress VARCHAR(50), LogInDate DATETIME)INSERT
INTO @UnLockSELECT
10, 'rkbabu', '111.111.111.111', 'Aug 24 2010 1:12AM' UNION ALLSELECT
10, 'rkbabu', '111.111.111.111', 'Aug 24 2010 2:03AM' UNION ALLSELECT
10, 'rkbabu', '111.111.111.111', 'Aug 24 2010 2:43AM' UNION ALLSELECT
10, 'rkbabu', '111.111.111.111', 'Aug 24 2010 3:02AM' UNION ALLSELECT
11, 'rkbabu', '111.111.111.111', 'Aug 24 2010 11:50PM'SELECT
* FROM @LockSELECT * FROM @UnLock
I want to get the result as difference between 'Aug 24 2010 1:05AM' in @Lock and 'Aug 24 2010 1:12AM' in @UnLock
'Aug 24 2010 2:00AM' in @Lock and 'Aug 24 2010 2:03AM' in @UnLock and so on.
We should use group by LogInDate, UserName, IpAddress
Finnally the difference of time should be sumed for LogInDate, UserName, IpAddress
Thanks,
Babu Kumarasamy.