Can NOT create Materialized View

Thanks
M. Mehta  

Please follow my example below:  

created 2 tables:  

select * from emp;  

    EMP_ID DEPT_ID SAL
---------- ---------- ----------

         1          1      20000
         2          1      50000
 

select * from dept;  

   DEPT_ID DEPT_NAME
---------- ----------

         1 HR
         2 IT
         3 CC
 

create materialized view (with out outer join): SQL> create materialized view mv_test build immediate refresh complete on commit as
  2 select count(*), b.dept_id, b.dept_name, sum(sal) salary, count(sal)
  3 from emp a, dept b
  4 where a.dept_id = b.dept_id
  5 group by b.dept_id, b.dept_name
  6 /  

Materialized view created.