What is self join with example?

The self join, as its name implies, joins a table to itself….

• The manager of the employee John Smith is the employee with Id 3, i.e., Tom Lanon.
• The manager of the employee Jane Anderson is the employee with Id 3, i.e., Tom Lanon.
• The manager of the employee Tom Lanon is the employee with Id 4, i.e., Anne Connor.

How do I find an employee’s self join manager?

SQL SELF JOIN

1. SELECT column1, column2, column3.
2. SELECT e.first_name || ‘ ‘ || e.last_name AS employee, m.first_name || ‘ ‘ || m.last_name AS manager FROM employees e INNER JOIN employees m ON m.employee_id = e.manager_id ORDER BY manager;

What are the best scenarios to use a self join?

Answer: The best example of self join in the real world is when we have a table with Employee data and each row contains information about employee and his/her manager. You can use self join in this scenario and retrieve relevant information.

How do I get my manager name from employee table?

job FROM EMP E JOIN EMP Y ON E. EMPNO=Y. MGR; This will give you distinct employee name who are managers.

Where to find manager ID in self join?

Other employees, who have a manager, have a numeric value in the manager_id column, which indicates the id of the manager. To retrieve the employee and manager data from the employees table, you use a self join as shown in the following statement:

Which is the best example of a self join?

Answer: The best example of self join in the real world is when we have a table with Employee data and each row contains information about employee and his/her manager.

How does self join work in real world?

One of the columns in the same table contains the ID of the manger, who is also an employee for the same company. Now all the employees and their managers are present in the same table. Let us see how Self Join works in the real world scenario now. Let us now connect the Employee table with itself with the help of INNER JOIN.

What does a self join do in Oracle?

Introduction to Oracle Self Join A self join is a join that joins a table with itself. A self join is useful for comparing rows within a table or querying hierarchical data. A self join uses other joins such as inner join and left join.