How to add values in tree nodes

I want to add LPV,RPV,LAmount,RAmount.

select sum(LPV) as Lv, sum(RPV) as Rv, sum(LAmount + RAmount) as Total from ( select leftn as SId, LPV, RPV, LAmount, RAmount from amount inner join (select @sid:=(select group_concat(leftn,',',rightn) from amount where find_in_set(sid, @nsid) >= 1), @nsid:=@sid as fset from amount, (select @nsid:='AMSJOXOLO',@sid='')v )gr on find_in_set(leftn,fset) where leftn <> '' union select rightn as SId, LPV, RPV, LAmount, RAmount from amount inner join (select @sid:=(select group_concat(leftn,',',rightn) from amount where find_in_set(sid, @nsid) >= 1), @nsid:=@sid as fset from amount, (select @nsid:='AMSJOXOLO',@sid='')v )gr on find_in_set(rightn,fset) where rightn <> '')x

When i am execute this above code, I got output like below:


But this addition program shows wrong output.

The original output is:

Lv         Rv        Total
19.5      21.5    2050

I need the addition query to show the original values like above output.
amount.sql