QUERYING TWO TABLE BUT not rquired 99% of the time

Question

I have two tables EMPLOYEE AND DEPARTMENT.
Most of the time I require to query only employee table (99% of the time),but there are times when I have to
query department table to get details about department
select e.emp_id,e.emp_age,e.department_desc from employee e,department d where e.department_id = d.deparmemnt_id and e.department_id = 1;
The problem is 99% of the time I dont need the join,that is 99% of the time I jsut need select * from employee because department_id is almost most of the time greater than 1.Wondering how can write just one query that will do the trick.
Thanks
M

Answer 1

this?
SQL> SELECT e.empno,e.ename,CASE WHEN e.DEPTNO=10 THEN
  2             (SELECT d.dname FROM DEPT d WHERE d.DEPTNO=e.DEPTNO) END Depratment_name
  3  FROM EMP  e;
     EMPNO ENAME      DEPRATMENT_NAM
      7369 SMITH
      7499 ALLEN
      7521 WARD
      7566 JONES
      7654 MARTIN
      7698 BLAKE
      7782 CLARK      ACCOUNTING
      7788 SCOTT
      7839 KING       ACCOUNTING
      7844 TURNER
      7876 ADAMS
      7900 JAMES
      7902 FORD
      7934 MILLER     ACCOUNTING
        12 1
       156 1
16 rows selected.