InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
What is self join, explain with example? |
|
Answer» Self-join is the one in which the same table is joined by itself to GET the desired output. We can understand self join in case of the below SCENARIO : Let's assume we have below table structure for Employee :
If we need to extract employee and manager information from the above table then the only option we have is to using self join. We can make a self join on the Employee table on JOINING ManagerID with EmployeeID. Please find below query which explains self join clearly : ALTHOUGH we can have other alternatives as well to get the same desired result set. It uses left outer Join: |
|