View Oracle PLSQL

SQL>
SQL>
SQL> CREATE TABLE departments
  2  (department_id           number(10)            not null,
  3   department_name      varchar2(50)      not null,
  4   CONSTRAINT departments_pk PRIMARY KEY (department_id)
  5  );
Table created.
SQL>
SQL>
SQL>
SQL> insert into departments ( department_id, department_name )
  2                    values( 1,             'Data Group' );
1 row created.
SQL>
SQL> insert into departments ( department_id, department_name )
  2                    values( 2,             'Purchasing' );
1 row created.
SQL>
SQL> insert into departments ( department_id, department_name )
  2                    values( 3,             'Call Center' );
1 row created.
SQL>
SQL> insert into departments ( department_id, department_name )
  2                    values( 4,             'Communication' );
1 row created.
SQL>
SQL>
SQL>
SQL> CREATE TABLE employees
  2  ( employee_id          number(10)      not null,
  3    last_name            varchar2(50)      not null,
  4    email                varchar2(30),
  5    hire_date            date,
  6    job_id               varchar2(30),
  7    department_id        number(10),
  8    salary               number(6),
  9    manager_id           number(6),
 10    CONSTRAINT           employees_pk PRIMARY KEY (employee_id),
 11    CONSTRAINT           fk_departments FOREIGN KEY (department_id) REFERENCES departments(department_id)
 12  );
Table created.
SQL>
SQL>
SQL> insert into employees( employee_id, last_name, email, hire_date, job_id, salary,department_id ,manager_id)
  2                values ( 1001, 'Lawson', 'lawson@g.com', '01-JAN-2002','MGR', 30000,1 ,1004);
1 row created.
SQL>
SQL> insert into employees( employee_id, last_name, email, hire_date, job_id, salary, department_id ,manager_id)
  2                values ( 1002, 'Wells', 'wells@g.com', '01-JAN-2002', 'DBA', 20000,2, 1005 );
1 row created.
SQL>
SQL> insert into employees( employee_id, last_name, email, hire_date, job_id, salary, department_id ,manager_id)
  2                 values( 1003, 'Bliss', 'bliss@g.com', '01-JAN-2002', 'PROG', 24000,3 ,1004);
1 row created.
SQL>
SQL> insert into employees( employee_id, last_name, email, hire_date, job_id, salary, department_id, manager_id)
  2                 values( 1004,  'Kyte', 'tkyte@a.com', SYSDATE-3650, 'MGR',25000 ,4, 1005);
1 row created.
SQL>
SQL> insert into employees( employee_id, last_name, email, hire_date, job_id, salary, department_id, manager_id)
  2                 values( 1005, 'Viper', 'sdillon@a .com', SYSDATE, 'PROG', 20000, 1, 1006);
1 row created.
SQL>
SQL> insert into employees( employee_id, last_name, email, hire_date, job_id, salary, department_id,manager_id)
  2                 values( 1006, 'Beck', 'clbeck@g.com', SYSDATE, 'PROG', 20000, 2, null);
1 row created.
SQL>
SQL> insert into employees( employee_id, last_name, email, hire_date, job_id, salary, department_id, manager_id)
  2                 values( 1007, 'Java', 'java01@g.com', SYSDATE, 'PROG', 20000, 3, 1006);
1 row created.
SQL>
SQL> insert into employees( employee_id, last_name, email, hire_date, job_id, salary, department_id, manager_id)
  2                 values( 1008, 'Oracle', 'wvelasq@g.com', SYSDATE, 'DBA', 20000, 4, 1006);
1 row created.
SQL>
SQL>  select department_name, count(*),
  2           to_char( (count(*)/total_emp.cnt)*100, '90.99' ) || '%' pct
  3      from departments,
  4           employees, ( select count(*) cnt from employees ) total_emp
  5     where departments.department_id = employees.department_id
  6     group by department_name, total_emp.cnt
  7     /
DEPARTMENT_NAME                                      COUNT(*) PCT
-------------------------------------------------- ---------- -------
Communication                                               2  25.00%
Data Group                                                  2  25.00%
Purchasing                                                  2  25.00%
Call Center                                                 2  25.00%
SQL>
SQL> drop table employees cascade constraints;
Table dropped.
SQL> drop table departments cascade constraints;
Table dropped.
SQL>