using at new in loop for not Key field

Hi,

How can i use "at new" in loop for not Key field ? if is that not possible, there is an alternative ?

i have Ztable with the following:

Key                         key                   key      key               Not key

Company code    -- docnr ---           year --  Item  --  invoice number

1000                     -- 1223333399      2015 --     1     --   1121314151516

I want to report by invoice number field.

thank for your input.