When saving data you may have wondered if converting a null value to another character i.e. a space, impacts disk space usage in your database.
Why would you convert a null to a space or dash? Well some people/organizations, rightly or wrongly, prefer this for reporting purposes or some other business requirement.
OK, lets review 3 common storage types, int, char and varchar:
Finally we get a difference of 3 bytes when using a null rather than another character when using varchar.
Conclusion, not all data types allow for space savings when using nulls.