Select non-task workorders, but include the costs of the tasks IBM's Maximo Asset Management platform has a WORKORDER table (265 columns).
Details:
The WORKORDER table contains two different kinds of rows:

WO records (istask = 0)
Task records (istask = 1).

The table has columns that store the actual costs (populated for both non-task WOs and for tasks):

actlabcost (actual labor cost)
actmatcost (actual material cost)
actservcost (actual services cost)
acttoolcost (actual tool costs)


View:
I've written a query/view that selects non-task WOs.
For those non-task workorders, the view rolls up the costs from the related tasks and summarizes them in these columns:

actlabcost_incltask
actmatcost_incltask
actservcost_incltask
acttoolcost_incltask
acttotalcost_incltask

I plan to use the view for multiple reports. So I've included all 265 columns in the view via select * (although, Oracle will convert the select * to actual column names when the view is created).
--WO_INCL_TASK_ACT_VW (non-task WOs, includes task actuals)
select 
    t.task_actlabcost, 
    t.task_actmatcost, 
    t.task_actservcost, 
    t.task_acttoolcost,
    t.task_acttotalcost,
    nt.actlabcost   + t.task_actlabcost     as actlabcost_incltask, 
    nt.actmatcost   + t.task_actmatcost     as actmatcost_incltask, 
    nt.actservcost  + t.task_actservcost    as actservcost_incltask, 
    nt.acttoolcost  + t.task_acttoolcost    as acttoolcost_incltask,
    t.task_acttotalcost + nt.actlabcost + nt.actmatcost + nt.actservcost + nt.acttoolcost as acttotalcost_incltask, 
    nt.*
from 
    workorder nt --non-task WOs
left join
    (
    select 
        parent,  
        sum(actlabcost)  as task_actlabcost, 
        sum(actmatcost)  as task_actmatcost, 
        sum(actservcost) as task_actservcost, 
        sum(acttoolcost) as task_acttoolcost,
        sum(actlabcost) + sum(actmatcost) + sum(actservcost) + sum(acttoolcost) as task_acttotalcost 
    from 
        workorder 
    group by
        parent,
        istask
    having
        istask = 1
    ) t                --tasks
    on nt.wonum = t.parent
where
    nt.istask = 0

Question:
The view works just fine. However, it's fairly lengthy for what it does.
Can it be improved?
I know you say that

I plan to use the view for multiple reports. So I've included all 265 columns in the view via select *

but given the truly absurd column count in that table, I would consider a select-splat to be a very last resort. Are you able to narrow this at all?
Generally your query seems sane. Since you say that the following columns are non-nullable,
sum(actlabcost) + sum(actmatcost) + sum(actservcost) + sum(acttoolcost)

should be equivalent to
sum(actlabcost + actmatcost + actservcost + acttoolcost)