Null position

Hi support,

I would like to ask that how we can know the null value having position from string ?

Example:

String > FIRST NAM

            123456789(total size of the above string)

Output>6 th position i need.because in the above string 6 position is a null value.please could you let me know how we can achive this using sql or plsql ?

Regards,

User420486