How do I use Fractile Function (Calculate Decile) to Count

[#1]

Greetings

I have the following Fields

PRODUCT_CODE, USER_ID, BALANCE

I have created an Expression to calculate the Decile as follows

=Fractile(BALANCE, 0.1)

Now I want to count the number of USER_ID's and SUM of BALANCE of the Decile.

How do I Count and Sum?

Thank you.