[1] Let describe more about the question ---

There is a list of numbers in column A, but the list does not contain a
fixed number of samples, and the number does not fixed within any range. On
the other words, sometimes, there are 100 numbers, or 1000 numbers and the
number can be any digits in length.

[2] What I want to do ---

I would like to measure the frequency on the listed numbers. Firstly, how to
list out all the possible numbers under column B within the list, and then
measure the frequency of occurrence of those numbers under column C, but the
amount of possible numbers is unknown for column B, if I input
{=Frequency(A:A,B:B)} on column C then #N/A occurs because some cells do not
contain any value.

Does anyone have any suggestions on how to measure frequency?
Thank for any suggestions
Eric