Ok to answer your question then, based on your tables:
1) is only applicable if you pass a particular user, like you can find everyone that makes more than person #2 and that would be:
SELECT ename FROM employee WHERE salary > (SELECT salary FROM employee where eno = 'your_input') ORDER BY salary desc;
2) this should be:
select ename, salary / (select sum(salary) FROM employee) from employee;
you might need to fix some syntax errors. but check on the phrasing of question 1, as it is not something done in MySQL.