11插入数据
INSERT INTO student VALUES ('A007', null,'女', '小华', '24-7月-15', 27,17891345129,32000,'工程部');
select * from student where xh is null;--查找某一项值为空
12 select coalesce(XH,0) from student--将空值转换为实际值
13按指定方式排序
select name,depo,sal from student order by sal desc;--按工资大小进行升序排列
14 select xh,depo,sal from student order by xh,sal desc;--按照优先次序从左向右排列
15继续插入数据
INSERT INTO student VALUES ('A008', 0805,'女', '小华', '21-7月-15', 37,17891345129,32000,'研发部');
INSERT INTO student VALUES ('A009', 0806,'女', '小华', '21-7月-15', 47,17891345129,11200,'研发部');
select name,birthday,telephone
from student order by substr(telephone,length(telephone)-2)
--查找姓名，生日，电话号码按照电话号码的最后两个字段排序
