Easy question - Is this valid SQL?

For (a), would this be valid SQL to achieve the purpose stated above?

SELECT DISTINCT s.first_name, s.last_name
FROM student s, mark_facts mf, employer e, instructor i, period p
WHERE s.student_id = mf.student_id
AND e.employer_name = 'Google'
AND e.employer_id = mf.employer_id
AND i.first_name = 'Fred'
AND i.last_name = 'Hollows'
AND i.instructor_id = mf.instructor_id
AND p.semester_no = '2'
AND p.year = '2007'
AND p.period_key = mf.period_key;

Thanks

 

Yes, it is (which you've probably discovered by now).