I am suggesting this as per my understanding of the problem

Write a stored procedure or a query inner joining all the three tables OrderHeader, OrderDetails and Orderchoices. Bind the stored...

You can also use ISNULL check for the datecolumns :

ISNULL(dbo.flightinfo.end_date,'') = ISNULL(b.end_date,'')

thereby avoiding an additional condition as

OR

(

dbo.flightinfo.end_date IS NULL AND b.end_date IS NULL

)

While the linked server is the best option for that, do not forget to give the credentials on which the linkedserver should run which otherwise would give you a security exception....

Did u set the intergrated security on in the datasource property?

Yeah,

This is a really good article and it reflects the thoughts going on in the minds of developers who have been working day and night on projects which ultimately are...