Mega Code Archive

Self join for employees and their managers

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 ); 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 * from employees; EMPLOYEE_ID LAST_NAME EMAIL HIRE_DATE JOB_ID DEPARTMENT_ID SALARY MANAGER_ID ----------- -------------------------------------------------- ------------------------------ --------- ------------------------------ ------------- ---------- ---------- 1001 Lawson lawson@g.com 01-JAN-02 MGR 1 30000 1004 1002 Wells wells@g.com 01-JAN-02 DBA 2 20000 1005 1003 Bliss bliss@g.com 01-JAN-02 PROG 3 24000 1004 1004 Kyte tkyte@a.com 13-JUN-98 MGR 4 25000 1005 1005 Viper sdillon@a .com 10-JUN-08 PROG 1 20000 1006 1006 Beck clbeck@g.com 10-JUN-08 PROG 2 20000 1007 Java java01@g.com 10-JUN-08 PROG 3 20000 1006 EMPLOYEE_ID LAST_NAME EMAIL HIRE_DATE JOB_ID DEPARTMENT_ID SALARY MANAGER_ID ----------- -------------------------------------------------- ------------------------------ --------- ------------------------------ ------------- ---------- ---------- 1008 Oracle wvelasq@g.com 10-JUN-08 DBA 4 20000 1006 8 rows selected. SQL> SQL> select employee_id, last_name, job_id, manager_id 2 from employees 3 order by employee_id 4 / EMPLOYEE_ID LAST_NAME JOB_ID MANAGER_ID ----------- -------------------------------------------------- ------------------------------ ---------- 1001 Lawson MGR 1004 1002 Wells DBA 1005 1003 Bliss PROG 1004 1004 Kyte MGR 1005 1005 Viper PROG 1006 1006 Beck PROG 1007 Java PROG 1006 EMPLOYEE_ID LAST_NAME JOB_ID MANAGER_ID ----------- -------------------------------------------------- ------------------------------ ---------- 1008 Oracle DBA 1006 8 rows selected. SQL> select e1.last_name "Employee", 2 e2.last_name "Reports To" 3 from employees e1 left outer join employees e2 4 on e1.manager_id = e2.employee_id 5 order by e1.employee_id 6 / Employee Reports To -------------------------------------------------- -------------------------------------------------- Lawson Kyte Wells Viper Bliss Kyte Kyte Viper Viper Beck Beck Java Beck Employee Reports To -------------------------------------------------- -------------------------------------------------- Oracle Beck 8 rows selected. SQL> SQL> SQL> drop table employees; Table dropped. SQL>