You can get an IDBResult2 interface, which provides the method GetFieldIndex:
if (ResultSet as IDBResult2).GetFieldIndex('SomeField') <> -1 then ...
For null, you can simply get the value and check if it's a null variant (VarIsNull).
You can get an IDBResult2 interface, which provides the method GetFieldIndex:
if (ResultSet as IDBResult2).GetFieldIndex('SomeField') <> -1 then ...
For null, you can simply get the value and check if it's a null variant (VarIsNull).