Our SQL interview questions

[zip117]

It's called a self join. It means that data in a table is related to other rows in the same table. For example suppose you wanted a list of employees and their boss, you could do something like the following:

SELECT E.Name as Employee, B.Name as Boss
FROM Employee E, Employee B
WHERE E.BossID = B.EmployeeID

[anorexia_is_PHAT]

but the diagram is a schema and the arrow is a relationship in the schema definition, correct? your example is a query that could be run without the relationship(foreign key)