Self join in Sql server

Question

Hi friends Can anybody define the term self join with simple example in sql server ?

Chintan Rathod · Answer

What is it? A self-join is simply a normal SQL join that joins one table to itself. This is accomplished by using table name aliases to give each instance of the table a separate name. When Useful? Joining a table to itself can be useful when you want to compare values in a column to other values in the same column. We have sample records in Employee table. Inner Join Example---- SELECT e1.Name EmployeeName  e2.name AS ManagerName FROM Employee e1 INNER JOIN Employee e2 ON e1.ManagerID = e2.EmployeeID Outer Join example--- SELECT e1.Name EmployeeName  ISNULL ( e2.name  'Top Manager' ) AS ManagerName FROM Employee e1 LEFT JOIN Employee e2 ON e1.ManagerID = e2.EmployeeID

Satyapriya Nayak · Answer

Hi Akshay Please refer the below link http://www.sql-statements.com/sql-self-join.html http://www.sqltutorial.org/sqlselfjoin.aspx Thanks

Sam Hobbs · Answer

Just search this web site for self join . The following are some of the results of that. Self Join SELF JOIN in SQL What is a self join? Table Join in SQL 2005 Joins in MySQL A self join is often used to create a hierarchical relationship such as a parts list of something manufactured or a hierarchy of employees and managers. See Creating drilldown hierarchical report using SQL Server reporting services 2005 for an article about an employees and managers hierarchy.

Prabhu Raja · Answer

Hi Self join is also like a normal join Where a table join itself. Example : Select a.empno a.empname from employee a inner join employee b on a.empno = b.empno