Consider the following SQL query on the university schema: SELECT AVG(salary) - (SUM(salary)/COUNT(*)) FROM instructor; We might expect that the result of this query is zero since the average of a set...

Consider the following SQL query on the university schema:
SELECT AVG(salary) - (SUM(salary)/COUNT(*))
FROM instructor;
We might expect that the result of this query is zero since the average of a set of numbers is defined to be the sum of
the numbers divided by the number of numbers. Indeed, this is true for the example instructor relation in Figure 2.1.
However, there are other possible instances of that relation for which the result would NOT be zero. Give one such
instance, and explain why the results would not be zero.