asp.net using c#

i need (logintime in one table and fixed working hours is eg:9 but a employee login at 10 o clock the delay hours is 1 hour . fixed working hours is saved in one table as companytime(tablename) and employee login time is saved in another table as logintime (table) i need to compare both the table and need the delay time )

Eg: Logintime is 10
fixed time is 9
----------
delay is 1 hour
-----------------