#8

  1  select empno, ename, sal, deptno
  2  from emp
  3  where sal < all
  4* (select Sal from emp where deptno = 30)
SQL>
SQL> /

     EMPNO ENAME             SAL     DEPTNO
---------- ---------- ---------- ----------
      7369 SMITH             800         20

#9

  1  select deptno, min(sal) + 1000
  2  from emp
  3  group by deptno
  4  having min(sal) + 1000 >
  5  (select avg(sal)
  6  from emp
  7* where deptno = 30)
SQL> /

    DEPTNO MIN(SAL)+1000
---------- -------------
        30          1950
        20          1800
        10          2300

#10

SQL> select empno, mgr, deptno from emp
  2  where (mgr, deptno) in
  3     (select mgr, deptno from emp
  4      where empno in (7900, 7902, 7934));

     EMPNO        MGR     DEPTNO
---------- ---------- ----------
      7900       7698         30
      7844       7698         30
      7654       7698         30
      7521       7698         30
      7499       7698         30
      7902       7566         20
      7788       7566         20
      7934       7782         10


#11

  1  select empno, deptno,
  2  (select dname from dept  where emp.deptno = dept.deptno)
  3* from emp
SQL> /

     EMPNO     DEPTNO (SELECTDNAMEFR
---------- ---------- --------------
      7369         20 RESEARCH
      7499         30 SALES
      7521         30 SALES
      7566         20 RESEARCH
      7654         30 SALES
      7698         30 SALES
      7782         10 ACCOUNTING
      7788         20 RESEARCH
      7839         10 ACCOUNTING
      7844         30 SALES
      7876         20 RESEARCH

     EMPNO     DEPTNO (SELECTDNAMEFR
---------- ---------- --------------
      7900         30 SALES
      7902         20 RESEARCH
      7934         10 ACCOUNTING


#12
  1  select deptno, dname from dept
  2* where exists (select empno from emp where emp.deptno = dept.deptno)
SQL> /

    DEPTNO DNAME
---------- --------------
        10 ACCOUNTING
        20 RESEARCH
        30 SALES

SQL>