A、select employees.lastname,orders.orderdate from employees left join orders on employees.employeeid=orders.employeeid
B、select employees.lastname,orders.orderdate from employees join orders on employees.employeeid=orders.employeeid
C、select employees.lastname,orders.orderdate from employees inner join orders on employees.employeeid=orders.employeeid
D、select employees.lastname,orders.orderdate from employees,orders where employees.employeeid=orders.employeeid