What's The Accepted Way To Retrieve Records In A SQL Table With Null Values Using A Visual Studio 2005 Table Adapter?

I'm using an ObjectDataSource in Visual Studio to retrieve records from a SQL Server 2005 database.

 I have a very simple dilemma.  In a table I have fields FirstName, Surname, Address1, Address2, Address3 etc. None of these are mandatory fields.

It is quite common for the user not to enter data in Address2, Address3, so the values are <null> in the SQL table.

In Visual Studio 2005 I have an aspx form where users can pass search parameters to the ObjectDataSource and the results are returned according to the passed in parameters.

The WHERE clause in my Table Adapter is:WHERE (Address1 LIKE @Address1 + '%') AND (Address2 LIKE @Address2 + '%') AND   (Address3 LIKE @Address3 + '%') AND (FirstName LIKE @FirstName + '%') AND (Surname LIKE @Surname + '%')

If, for example, I simply want to search WHERE FirstName LIKE ‘R’, this does not return any results if the value of Address3 is <null>

My query is this: Could someone please show me the best way in Visual Studio 2005 to return records even if one of the Address fields is <null>.

For reference, I have tried: Address3 LIKE @Address3 + '%' OR IS NULLThis does work, however itsimply returns every instance where Address3 is <null>  (accounting for about 95% of the records in the database). Thanks in advance Simon