Nice question. This trips up a lot of people new to SQL and seems to lead to a lot of negative feelings towards NULL values.
(NULLs aren't bad, they're just often misunderstood!!)
Totally agree. 🙂
I actually love NULLS, but then again I'm more familiar with them my devs are.
The sad thing are the number of tables with NULLable columns, but the apps explode when the data is actually NULL because the guys who made the database 10 years before I started didn't handle NULL correctly, or didn't make the column NOT NULL.
Ah one day we'll get them all cleaned up... 80 databases.... over 1500 tables used by nearly 50 applications.... probably not soon.