Hi, am kind of new to oracle and I need an immediate help.

I have a table that has a column that is NULL and the datatype is varchar2(9).
I want to decrease the datatype to varchar2(3) so I issued this command:

alter table emp modify(
ename varchar2(3) NULL;

and I received this error message:
ora-01441: column to be modified must be empty to decrease column length.

So I looked under documentation's error messages but it did not really help.

Can any body please show me the specific commands to do this(empty the column to be modified) so that I can change the varchar(9) to varcha2(3) without any problem?

thanks