SQL & PL/SQL

Hi All,

I want all numbers have 2 zeros after decimal point like below.

14 ==> 14.00

4.6 ==> 4.60

2.4 ==> 2.40

5.45 ==> 5.45

However, at the sametime it shouldbe NUMBER, not CHAR. I am trying to use the following formula. However it doesn't work.

select to_number(to_char(4.2, '99D99')) from dual; ==>  4,2  (The result should be 4.20 instead of 4.2)

select to_number(to_char(4.2, '99.99')) from dual; ==> ORA-01722: ERROR

So what should I do?

Thanks in advance.