Need help to write an interesting query

Question

I need some help in framing the query for the following scenario.
I have three tables (in general)
Departments
DNO (PK)
DNAME
Employees
DNO (FK to DNO in Departments)
ENO (PK)
CODE
History
seqid (PK)
ENO (FK to ENO in Employees)
The summary of the data in Employees table looks like below:
DNo           No of employees
10              10
20               5
30               8so there will be total of 23 records in employees table. I want to check if all the 10 employees from dept 10 are existing in history table and if exists I want to display the dno and dname from the employees and departments tables respectively. Even if the history table has 9 employees out of 10 from employees table I don't want the query to retrieve that dept details.
Can any one help me with this?
Meanwhile I will also try my level best and let you people know if I come up with anything.
Thanks for your time

Answer 1

Here the example that will help you.
emp_test is the history table for you. You can change ct>9SQL> SELECT * FROM
  2  ( SELECT empno ,
  3          ename ,
  4       e.deptno,dname,
  5       COUNT(*) OVER(PARTITION BY e.deptno ORDER BY e.deptno) ct
  6     FROM EMP e ,DEPT d
  7     WHERE e.deptno=d.deptno
  8     AND EXISTS (SELECT 'x' FROM EMP_TEST T
  9                 WHERE T.empno=e.empno))
10  WHERE ct>3;
     EMPNO ENAME          DEPTNO DNAME                  CT
      7499 ALLEN              30 SALES                   4
      7698 BLAKE              30 SALES                   4
      7654 MARTIN             30 SALES                   4
      7521 WARD               30 SALES                   4
SQL> set linesize 300
SQL> select * from emp_test;
     EMPNO ENAME                JOB              MGR HIREDATE         SAL       COMM     DEPTNO
      7369 SMITH                CLERK           7902 17-DEC-80      800.2                    20
      7499 ALLEN                SALESMAN        7698 20-FEB-81       1600        300         30
      7521 WARD                 SALESMAN        7698 22-FEB-81       1250        500         30
      7566 JONES                MANAGER         7839 02-APR-81       2975                    20
      7654 MARTIN               SALESMAN        7698 28-SEP-81       1250       1400         30
      7698 BLAKE                MANAGER         7839 01-MAY-81       2850                    30
      7782 CLARK                MANAGER         7839 09-JUN-81       2450                    10
7 rows selected.
SQL> select * from emp;
     EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO
      7369 SMITH      CLERK           7902 17-DEC-80      800.2                    20
      7499 ALLEN      SALESMAN        7698 20-FEB-81       1600        300         30
      7521 WARD       SALESMAN        7698 22-FEB-81       1250        500         30
      7566 JONES      MANAGER         7839 02-APR-81       2975                    20
      7654 MARTIN     SALESMAN        7698 28-SEP-81       1250       1400         30
      7698 BLAKE      MANAGER         7839 01-MAY-81       2850                    30
      7782 CLARK      MANAGER         7839 09-JUN-81       2450                    10
      7788 SCOTT      ANALYST         7566 19-APR-87       3000                    20
      7839 KING       PRESIDENT            17-NOV-81       5000                    10
      7844 TURNER     SALESMAN        7698 08-SEP-81       1500          0         30
      7876 ADAMS      CLERK           7788 23-MAY-87       1100                    20
      7900 JAMES      CLERK           7698 03-DEC-81        950                    30
      7902 FORD       ANALYST         7566 03-DEC-81       3000                    20
      7934 MILLER     CLERK           7782 23-JAN-82       1300                    10formatted
Message was edited by:
devmiral