My Contract flag shud have the above three values as C,N,P which I need to be created.
Serial Number Contract Start Date End Date Contract flag
A12B34 12345 04/23/2012 04/23/2013 P
B12D34 54321 04/23/2012 04/23/2014 C
T12B35 22345 04/23/2012 04/23/2012 N
P->displays all serial numbers ie., A12B34 because it used to have a validity but now it has expired as of today.
C->displays all serial numbers ie., B12D34 because it is still valid as of today.
N->displays all serial numbers ie., T12B35 because it start date is equal to end date.