Does it matter what the field is filled with - text or all NULL values?

Question

Database

The field is of data type VARCHAR2(128)
Whether the field is filled with text or all NULL values.
Will there be a difference in the amount of data occupied on the disk or not?
It seems like VARCHAR2 - dynamically allocates memory and with NULL it should be used less?

Answer 1

Depends on the DBMS. In MSSQL null and '' are different values, in Oracle null and '' are the same. With NULL, it's more likely that less space will be used.