You either have actual NULLs in your tables or you have implied NULLs that don't exist in the actual tables but still come up when you do LEFT JOINs etc.
I don't think NULLs are actually a problem in SQL. It's not like we're talking about pointers, it won't cause your server to crash if you use them wrong. NULLs in SQL are fine.
> don't use NULL
I'm not sure this part is realistic to do in a non-trivial setup. At the very least it's not a common thing to do.
You either have actual NULLs in your tables or you have implied NULLs that don't exist in the actual tables but still come up when you do LEFT JOINs etc.
I don't think NULLs are actually a problem in SQL. It's not like we're talking about pointers, it won't cause your server to crash if you use them wrong. NULLs in SQL are fine.
They're far worse than null pointers. They can cause subtle bugs that lead to queries that appear to work but result in missing or incorrect data.