2a)
SELECT Office, Email
FROM EMPLOYEE
WHERE Firstname = 'John' AND Lastname = 'Smith'

2b)
SELECT Days
FROM Vacation V JOIN Employee E ON V.EmployeeID = E.EmployeeID
WHERE E.Firstname = 'John' AND E.Lastname = 'Smith'

2c)
SELECT Firstname, Lastname
FROM Employee E JOIN Vacation V ON V.EmployeeID = E.EmployeeID
WHERE V.Days = '0

2d)
SELECT DepartmentName
FROM DEPARTMENT
WHERE DepartmentID IN (
    SELECT DepartmentID
    FROM
        (
        SELECT  E.DepartmentID, SUM(V.days) suma
        FROM VACATIONS as V JOIN EMPLOYEE as E
        ON V.EmployeeID = E.EmployeeID
        GROUP BY E.DepartmentID
        ) as abc
    WHERE abc.suma =
        (SELECT  MAX(def.suma)
            FROM
                (
                SELECT  E.DepartmentID, SUM(V.days) suma
                FROM VACATIONS as V JOIN EMPLOYEE as E
                ON V.EmployeeID = E.EmployeeID
                GROUP BY E.DepartmentID
                ) as def
          )
    );




OR

SELECT DepartmentName
FROM DEPARTMENT
WHERE DepartmentID IN (
    SELECT DepartmentID
    FROM
        (
        SELECT  E.DepartmentID, SUM(V.days) suma
        FROM VACATIONS as V JOIN EMPLOYEE as E
        ON V.EmployeeID = E.EmployeeID
        GROUP BY E.DepartmentID
        ) as abc
    WHERE abc.suma =
        (SELECT  MAX(suma)
         FROM abc )
    );