you don't have to complicate things like that. let me give an example:
select ID, NAME, DURATION-DATEDIFF(d, START, GETDATE())as SUBS_LEFT,
(case when DATEADD(d, DURATION, START)>GETDATE() then 0 else 1 end) IS_ENDED
from USER_PROFILE
then read here:
http://msdn.microsoft.com/en-us/library/314t4see.aspx[
^]
and here:
http://msdn.microsoft.com/en-us/library/33w255ac%28v=vs.110%29.aspx[
^]
1- create a project
2- add a dataset
3- create your datatable with the given query
4- place a gridview on your form.
5- set the datasource of the gridview as the datatable of the dataset
all code is automatically generated by both dataset designer and form designer. you don't need to write anything. if you like, you can change all that code later according to your needs. that is all.
[added]
select ID, NAME, DURATION-DATEDIFF(d, START, GETDATE())as SUBS_LEFT,
(case when DATEADD(d, DURATION, START)>GETDATE()
then convert(varchar, DURATION-DATEDIFF(d, START, GETDATE()))
else 'Expired' end) IS_ENDED
from USER_PROFILE