The default date fromat in MySql is: (YYYY-MM-DD). So you may have to change that in the hospitalinsert file.
The format '20-Feb-1981' is Oracle default format.

//1
select * 
from Department;

//2
select EmployeeName,JobType,Salary 
from Employee;

//3
select EmployeeName, Dept 
from Employee
where EmployeeId = '7369';

//4
select * 
from Employee, StaffEmployee
where Employee.EmployeeId = StaffEmployee.EmployeeId
and StaffEmployee.Classification = 'CLERCK';

//5
select EmployeeName,Salary
from Employee
where Salary > 2850;

//6
select EmployeeName,Salary
from Employee
where Salary < 1500
or Salary > 2850;

//7
//The default date fromat in MySql is: (YYYY-MM-DD). 
//So you may have to change that in the insert statements.
//The format '20-Feb-1981' is Oracle default format.

select EmployeeName,JobType, DH
from Employee
where DH between '20-Feb-1981' and '01-May-1981'
order by DH asc;

//8
select EmployeeName,Dept
from Employee
where Dept = '20'
or Dept = '10'
order by EmployeeName asc;

//9
select EmployeeName,Salary
from Employee
where Dept = '10'
and salary >1500;

//10
select EmployeeName,JobType
from Employee
where manger is null;

//11
select EmployeeName,Salary, Commission
from Employee
where Commission is not null
ORDER BY  Salary DESC,  Commission DESC;

//12
select EmployeeName
from Employee
where EmployeeName LIKE '%L%L%'
and dept = '10'
or manager = '7782';

//13
select Employee.EmployeeName,Employee.dept, Department.DeptName
from Employee, Department
where Employee.Dept = Department.DeptId;

//14
select distinct Employee.JobType, Department.DeptLocation
from Employee, Department
where Employee.Dept =  Department.DeptId
and Employee.dept = '30'

//15
select Employee.EmployeeName,Department.DeptName,Department.DeptLocation
from Employee, Department
where Employee.Dept = Department.DeptId
and Employee.Commission is NOT null;


//16
//Assumption: employee works where his/her Department is located.
select Employee.EmployeeName, Employee.JobType, Employee.dept, Department.DeptName
from Employee, Department
where Employee.Dept = Department.DeptId
and Department.DeptLocation = 'DALLAS';

//17
select JobType, count(EmployeeId)
from Employee
group by JobType;

//18
select count(*)
from Employee
where manager IN 
(select distinct manager
from Employee);

//19
select JobType, avg(Salary)
from Employee
group by JobType;

//20
//Note if MILLER does not exist then  MAX(Salary) returns 0.
select EmployeeId, EmployeeName
from Employee
where salary >
(select MAX(Salary)
from Employee
where EmployeeName = 'MILLER')

//21
//Note: There may be more than one MILLER that is why I used IN insead of = .
select EmployeeId, EmployeeName
from Employee
where JobType IN
(select JobType
from Employee
where EmployeeName = 'MILLER');

//22
//Note: MIN() will ignore NULL Salaries.
select EmployeeName,JobType,Salary
from Employee
where Salary =
(select MIN(Salary)
from Employee);