Oracle 11g: update with group by

Question

DB. 11.2.0.2.0
Hello
This feels as though it should be simple. The below code tries to update the Activities table with the sum of staff hours (worked out from two other tables).
The select works fine:
select a.activities_id, sum((t.st_proportion*s.staff_time)*7*(t.st_enddate-t.st_startdate)/100)
from aa_wl_activities3 a
join aa_wl_stafftime2 t
on a.activities_id=t.st_activity_id
join aa_wl_staff s
on t.st_staff_id=s.staff_id
group by a.activities_idand produces data like this:
7    700
6    700
44  700
41  700
update aa_wl_activities3 a
set a.activities_stafftime = sum((t.st_proportion*s.staff_time)*7*(t.st_enddate-t.st_startdate)/100)
join aa_wl_stafftime2 t
on a.activities_id=t.st_activity_id
join aa_wl_staff s
and t.st_staff_id=s.staff_id
group by a.activities_idI get this error:
ORA-00934: group function is not allowed hereFrom various bits of googling, it is possible to update using an aggregate function - I want to check it's possible in Oracle SQL and if anyone can spot anything wrong with my code
Thanks
Emma

Answer 1

emma-apex wrote:
From various bits of googling, it is possible to update using an aggregate function - I want to check it's possible in Oracle SQL and if anyone can spot anything wrong with my codeYes, it's possible but you have to do it with a correlated subquery that computes the sum for each row of the target table :
update aa_wl_activities3 a
set a.activities_stafftime =
  select sum(
           (t.st_proportion * s.staff_time)
         * 7
         * (t.st_enddate - t.st_startdate)
         / 100
  from aa_wl_stafftime2 t
       join aa_wl_staff s on s.staff_id = t.st_staff_id
  where t.st_activity_id = a.activities_id
;(Or MERGE as suggested)