sql - Divide does nothing -

I am trying to create percentile scores, my query generates the correct rank, but the division does nothing (rank score Instead of in the column)

  "/" (rank () "over" (by order "disk io")  

I also After selecting it, it has tried to generate rank and divided it, but it has only one result.

 (code "SELECT ...") "/" ("disk io score" Enumeration (*)) "Score" ... from (.... rank) "object" "... ...  

thanks, buzzie

  Select "System_Name", "/" (the command by "disk ioO"), "disk io", "disk io"  

Div class = "post-text" itemprop = "text">

Looks like you're using composite COUNT (*) instead of analytical.

Try:

  SELECT RANK () over (...) / COUNT (*) over (...)  

and you post the full query ( GROUP BY section)?