Find a SQL query that computes a set difference and returns false positive(s) over a database with null values. You may show the correctness of your answer using an example.

Write a SQL statement to prepare a list with salesman name, customer name and their cities for the salesmen and customer who belongs to the same city.

Given this image, write an SQL query to return a set of results where each row contains the car in the race and its colors

Write an SQL query to fetch the EmpId and FullName of all the employees working under Manager with id – ‘986’.

Propose and explain good indices (tree, hash, cluster, etc.) to support the following query. You do not need to write the SQL statements. SELECT D.DName, S.SName FROM Students S, Departments D WHERE S.Did = D.Did %3D