What is a mutating table error and how can you get around it?

Question

How we can get nth max salary from Employee Table (EMP_ID, Salary)

Emp_id salary
1 1000
3 2000
4 16000
2 10000
7 19000
8 12000

e.g. for 3rd max salary, salary is 12000 so answer will be emp_id : 8

Answer 1

This happens with triggers. It occurs because the trigger is trying to update a row it is currently using. The usual fix involves either use of views or temporary tables so the database is selecting from one while updating the other