The NULL in C means zero or void.Also its something that is uniform across the C program.In Oracle though you cant even compare two NULL values to be equal.NULL in oracle means nothing or no value.

Nulls can be compared in Oracle

1) Select 1 from dual where null is null;

- results 1

2) select 1 from scott.emp where ename is null

- if ename is null results 1 will be output

When you store data in oracle its terminated with a zero byte.

For example when you store HELLO its stored as

5HELLO where is the zero byte. When you dont store any data specifically or when the variable is null it contains zero byte stored in 2byte length indicator

In other words null is still a zero byte data stored in 2bytes.

Example. - .

Null in C is not garbage value that is a misconception. Null in C also is a zero byte character - null character ' '

If the variable is not initialized the location may contain some values which could be considered as garbage as its unpredictable.