题解 | #获取有奖金的员工相关信息。#

# SELECT e.emp_no, e.first_name, e.last_name, eb.btype, s.salary,
#     (CASE 
#     WHEN eb.btype = 1 THEN s.salary * 0.1
#     WHEN eb.btype = 2 THEN s.salary * 0.2
#     ELSE s.salary * 0.3
#     END) bonus
# FROM emp_bonus  eb, employees  e, salaries  s
# WHERE eb.emp_no = e.emp_no
# AND s.emp_no = e.emp_no
# AND s.to_date='9999-01-01'
##上面是别人的作业，不知道为什么等价于下面的join，请大神回复解释一下这里的用法，谢谢

SELECT e.emp_no, e.first_name, e.last_name, eb.btype, s.salary,
    (CASE 
    WHEN eb.btype = 1 THEN s.salary * 0.1
    WHEN eb.btype = 2 THEN s.salary * 0.2
    ELSE s.salary * 0.3
    END) bonus
FROM emp_bonus eb join employees  e on eb.emp_no = e.emp_no join
 salaries  s on s.emp_no = e.emp_no
where s.to_date='9999-01-01'