Oracle: Using CTE with update clause

Question

Can I make an update using common table expression in oracle database?

I am getting error ORA-00928: missing SELECT keyword when I am trying this:

Answer 1

Basing on another answer on correlated update of key-preserved view, here is another possible option to use CTE with update in Oracle SQL avoiding duplication of where clause:

update (
    with cte as (select avg(salary) average_salary from instructor)
    select id, salary, cte.average_salary from instructor cross join cte
    where 
)
set salary = case
    when salary <= average_salary/2 then salary * 1.1 
    when salary <= average_salary then salary * 1.05 
    else salary * 1.03                                     
end

In case of self-join this can be simplified to CTE-less version:

update (
    select id, salary, (select avg(salary) from instructor) average_salary 
    from instructor
    where 
)
set salary = case
    when salary <= average_salary/2 then salary * 1.1 
    when salary <= average_salary then salary * 1.05 
    else salary * 1.03                                     
end