| Subject | Re: check if a select return value |
|---|---|
| Author | Svein Erling |
| Post date | 2003-09-10T12:05:22Z |
> When I don't assign any value to a variable, the default value forNo, it is not a value at all. NULL is a state meaning that the value is unknown. All types can be unknown, and NULL differ from any value in that whatever you compare it to, it returns NULL. The same goes for any assignment, NULL + 5 is still NULL (if you did not know how much money you had in your wallet, you still don't know how much you have after putting some more money into it).
> integer are null ? and for varchar? where can I see the default
> value for the types?
Set