Guid Null Comparison issues

Question

I have what seems to be a simple linq statement:

 

Guid? parentGuid = null;

            if (root != null)
                parentGuid = root.ParentGuid;

            var nodes = (from n in _db.Navigations where n.ParentGuid == parentGuid select n);

 

The problem is if the parent Guid is null, linq does not output sql correctly as I would expect ie. "select * from table where ParentGuid Is Null".  It uses a comparison operator instead (select * from table where ParentGuid = @p1), which will not return rows because ansii_nulls is always set to on by default, and from what I understand I can't change this programmically without creating custom stored procs.  I've tried changing ansi_nulls to off on my database, but the ado.net connection overrides the default.

 

Anyone have a solution to this problem?  Thanks in advance.

 

 

Answer 1

 

Guid? parentGuid = null;

            if (root != null)
                parentGuid = root.ParentGuid;

            var nodes = (from n in _db.Navigations where n.ParentGuid == parentGuid || (n.ParentGuid == null && parentGuid == null) select n);

Answer 2

 

Thanks alot Kris, this was exactly what I was looking for.