Self Join - Sql server
Self-joins : A self-join is a query in which a table is joined to itself. Self-joins are used to compare values in a column with other values in the same column in the same table
Example: In this example i am tring to insert data into Employee table with emp id, manager id. Manager id referes same tables emplid. Finally by using innerjoin i wanted to get data with manager name rather than manager id.
1. Create table
CREATE TABLE dbo.Employee
(
empId int NOT NULL IDENTITY (1, 1),
empName nvarchar(50) NOT NULL,
managerId int NULL
) ON [PRIMARY]
2. Insert Data into Table
1,Madhu,NULL
2,Bala,1
3,Krishna,1
4,Ram,1
3. SQL Query - Self Join
select a.empId, a.empName as Employee , b.empName as ManagerName
from Employee a, Employee b where b.empId=a.managerId
4. Output
2,Bala,Madhu
3,Krishna,Madhu
4,Ram,Madhu
Posted by
at
06:11:33
