List all employee's names and their managers by manager name using an inner join

Question

The following is my CREATE TABLE script:

create table EMPLOYEES
    (EmpID    char(4)         unique Not null,
     Ename    varchar(10),
     Job      varchar(9),
     MGR      char(4),
     Hiredate date,
     Salary   decimal(7,2),
     Comm     decimal(7,2),
     DeptNo   char(2)         not null,
         Primary key(EmpID),
         Foreign key(DeptNo) REFERENCES DEPARTMENTS(DeptNo));

The following is my INSERT script:

insert into EMPLOYEES values (7839,'King','President',null,'17-Nov-11',5000,null,10);
insert into EMPLOYEES values (7698,'Blake','Manager',7839,'01-May-11',2850,null,30);
insert into EMPLOYEES values (7782,'Clark','Manager',7839,'02-Jun-11',2450,null,10);
insert into EMPLOYEES values (7566,'Jones','Manager',7839,'02-Apr-11',2975,null,20);
insert into EMPLOYEES values (7654,'Martin','Salesman',7698,'28-Feb-12',1250,1400,30);
insert into EMPLOYEES values (7499,'Allen','Salesman',7698,'20-Feb-11',1600,300,30);
insert into EMPLOYEES values (7844,'Turner','Salesman',7698,'08-Sep-11',1500,0,30);
insert into EMPLOYEES values (7900,'James','Clerk',7698,'22-Feb-12',950,null,30);
insert into EMPLOYEES values (7521,'Ward','Salesman',7698,'22-Feb-12',1250,500,30);
insert into EMPLOYEES values (7902,'Ford','Analyst',7566,'03-Dec-11',3000,null,20);
insert into EMPLOYEES values (7369,'Smith','Clerk',7902,'17-Dec-10',800,null,20);
insert into EMPLOYEES values (7788,'Scott','Analyst',7566,'09-Dec-12',3000,null,20);
insert into EMPLOYEES values (7876,'Adams','Clerk',7788,'12-Jan-10',1100,null,20);
insert into EMPLOYEES values (7934,'Miller','Clerk',7782,'23-Jan-12',1300,null,10);

The following is my SELECT script:

select distinct e.Ename as Employee, m.mgr as reports_to
from EMPLOYEES e
inner join Employees m on e.mgr = m.mgr;

Im getting the employees with their corresponding manager's ID;

Ford    7566
Scott   7566
Allen   7698
James   7698
Martin  7698
Turner  7698
Ward    7698
Miller  7782
Adams   7788
Blake   7839
Clark   7839
Jones   7839
Smith   7902

How do I list the manager name as well? *Am I doing the right inner join?*

Answer 1

Add m.Ename to your SELECT query:

select distinct e.Ename as Employee, m.mgr as reports_to, m.Ename as Manager
from EMPLOYEES e
inner join Employees m on e.mgr = m.EmpID;

Answer 2

Your query is close you need to join using the mgr and the empid

on e1.mgr = e2.empid

So the full query is:

select e1.ename Emp,
  e2.eName Mgr
from employees e1
inner join employees e2
  on e1.mgr = e2.empid

See SQL Fiddle with Demo

If you want to return all rows including those without a manager then you would change it to a LEFT JOIN (for example the president):

select e1.ename Emp,
  e2.eName Mgr
from employees e1
left join employees e2
  on e1.mgr = e2.empid

See SQL Fiddle with Demo

The president in your sample data will return a null value for the manager because they do not have a manager.