不使用case,就是将所有的情况列出来 select employees.emp_no,first_name, last_name, cal_emp_bonus.btype,salary,salary*cal_emp_bonus.rate as bonus from salaries, employees, ( select emp_no, btype, btype*0.1 as rate from emp_bonus where btype in(1,2) union select emp_no, btype, 0....