SQL学习TASK06

section A
1.创建员工信息表：
CREATE TABLE Employee
(s_product_id char(4) NOT NULL,
s_name VARCHAR(32) NOT NULL,
s_salary INTEGER,
s_department_id INTEGER);

创建部门信息表：
CREATE TABLE department
(d_id char(4) NOT NULL,
d_name VARCHAR(32) NOT NULL
);

插入员工信息表数据：
INSERT INTO employee VALUES(‘1’,‘Joe’,70000,1);
INSERT INTO employee VALUES(‘2’,‘Henry’,80000,2);
INSERT INTO employee VALUES(‘3’,‘Sam’,60000,2);
INSERT INTO employee VALUES(‘4’,‘Max’,7000,1);

记录问题：
为什么姓名和薪水不匹配

2.改变相邻两个同学的位置
如果学生人数是奇数，则不需要改变最后一个同学的座位。
select s.id , s.student from
(
select id-1 as id ,student from seat where mod(id,2)=0
union
select id+1 as id,student from seat where mod(id,2)=1 and id !=(select count() from seat)