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

Since average salary just a scalar value you can do

update instructor
   set salary = case
       when salary <= (select avg(t.salary) from instructor t) then salary * 1.05 
       else salary * 1.03                                     
   end

In that case Oracle first compute the average (say 1234.4567) and then perform the update.