How to select null values with LINQ to SQL and DbLinq?

Question

When I

bool? isApproved = null;
db.Table.Where(item => item.IsApproved == isApproved).Count();

the last line value is 0. But when I

db.Table.Where(item => item.IsApproved == null).Count();

the value is correct.

I'm using SQLite, DbLinq and DbMetal.

Answer 1

I have seen it done like this:

 db.Table.Where(
            item => item.IsApproved.HasValue == isApproved.HasValue && 
            (!item.IsApproved.HasValue || item.IsApproved.Value==isApproved.Value ) 
 ).Count();