尝试：

  SELECT  e .ID，e.Name，d.Name  AS  mangername 
 FROM 员工e 
 LEFT   JOIN  employee d  ON  e。经理ID = d.id 

In employee tables

ID Name Mangerid
1 raju Null
2 suresh 1
3 mohan 2

excepted table as

ID Name Mangername
1 raju Null
2 suresh raju
3 mohan suresh

What I have tried:

I have used self join in this scenario.

select e.ID, e.Name, d.Name as mangername from employee e self join employee d on e.id=d.Mangerid

I am not getting correctly.

Try:

SELECT e.ID, e.Name, d.Name AS mangername 
FROM employee e 
LEFT JOIN employee d ON e.ManagerID=d.id