Q:

Using Concat Operator ( || ) the Integer Part of is not shown for floating numbers

When I am writing a SELECT query in Oracle using concat || operator  to concatenate a decimal number and a string. Then for values that have integer part as zero is not shown.
But when I am only selecting Number the Integer part is shown.
My SQL Query Structure :-
SELECT
NUMBER_VAL ||
STRING_VAL
FROM MY_TABLE;

for E.g (selecting only Number):- 
SELECT 0.1 FROM DUAL;

I am getting Result: 0.01
E.g (Selecting Number and String Concatenated) :-
SELECT 0.01 || 'ABCD' FROM DUAL;

I am Getting Result: .01ABCD
Desired Result: 0.01ABCD
Can anyone help me how can I achieve the desired result.

This is in Addition to Rics Answer .
The Data type of NUMBER_VAL was NUMBER(9,4).
And that's why I had to Use the Format '99990.9999'

A:

Use to_char function and the appropriate number format:
SELECT
to_char(NUMBER_VAL,'0.99') ||
STRING_VAL
FROM MY_TABLE;

