3. (4.5 points) (Note: Read the schema of each table in the university database from ddl.sql or using schema before working on this problem.) Write the following queries in SQL, using the university schema. (You should actually check the queries you write on the database (a) to find the names of all instructors whose salary is more than the 90% of the average salary of all instructors. average salary. students enrolled in the section, if the section had at least 2 students. (b) to find the names of all instructors whose salary is more than the 90% of the department (c) for each course section offered in 2009, find the average total credits (tot.cred) of all 3. (4.5 points) (Note: Read the schema of each table in the university database from ddl.sql or using schema before working on this problem.) Write the following queries in SQL, using the university schema. (You should actually check the queries you write on the database (a) to find the names of all instructors whose salary is more than the 90% of the average salary of all instructors. average salary. students enrolled in the section, if the section had at least 2 students. (b) to find the names of all instructors whose salary is more than the 90% of the department (c) for each course section offered in 2009, find the average total credits (tot.cred) of all