About for update clause

Question

hi, i want to lock some rows that i've selected in a program. so, i use a for update clause. Here is my query:
SELECT *
FROM (
     SELECT name, age, classe, average
     FROM student
     WHERE average >= '15'
     AND warning is NULL
     AND status = '1'
     ORDER BY age
     FOR UPDATE OF average)
WHERE ROWNUM <= 5
the problem is that the oracle server always return this message:
ORA-00907: Parenthèse de droite absente
May you tell me what's wrong with this query? according to the Oracle message, it seems that i don't close a bracket,but it is not the case.So what it is the problem?
thanks.

Answer 1

It seems that you cannot have a FOR UPDATE clause in a inline view and that you cannot use the FOR UPDATE clause for an inlinve view if the inline view has an ORDER BY clause.
One solution is to create a temporary table to store the rowids of the table your want to select for update.
Example:
create global temporary table student5
( orowid rowid )
on commit preserve rows;
insert into student5
select rowid
from (select rowid
from student
where average >= 15
and warning is null
and status = '1'
order by age)
where rownum <= 5;
select * from student where rowid in (select orowid from student5) for update;Note also that if student.average column is numeric, you should not use quotes for '15'.