SQL 建表与查询 HTML计算时间差

create database xue1
go
--创建数据库
use xue1
go
--引用数据库
create table xinxi
(
   code int,
   name varchar(20),
   xuehao decimal(10),
   brithday decimal(10),
)
--创建信息表
insert into  xinxi values(1,'张三',2016042701,2016-4-27)
insert into  xinxi values(2,'李四',2016042702,2016-4-27)
insert into  xinxi values(3,'王五',2016042703,2016-4-27)
insert into  xinxi values(4,'马六',2016042704,2016-4-27)
insert into  xinxi values(5,'赵七',2016042705,2016-4-27)
insert into  xinxi values(6,'秦八',2016042706,2016-4-27)
--输入信息

--查询所有信息
select * from student
--查询学号为6的人的所有信息
select * from student where code=6
--查询学号为8的人的姓名
select name from student where code=8
--查询所有人的姓名
select name from student
--查询24岁以上的人的所有信息
select * from student where age>24
--身高超过175的所有人的姓名
select name as 姓名 from student where height>175
--查询总数
select COUNT(name) from student
--查询年龄超过24的人数
select COUNT(*) from student where age>24

--order by  排序   默认从小到大排列
select *from student order by age
--从大到小排列    desc
select *from student order by age desc

聚合函数

--AVG   平均数
select AVG(age) as 平均年龄 from student
select AVG(height) as 平均身高 from student

--SUM    求和
select SUM(age) from student
select SUM(height) from student

--MAX   最大值
select MAX(age) from student
select MAX(height) from student

--MIN   最小值
select MIN(age) from student
select MIN(height) from student

--COUNT  个数
--查询总数
select COUNT(name) from student
--查询年龄超过24的人数
select COUNT(*) from student where age>24

--分组  group by
select sex from student group by sex
--gre=oup by     having 聚合函数
select sex from student group by sex having COUNT(*)>5

--修改表中的数据
update student set age=18 where name='薛岩'

--增加一列
use Z1p10320
go
Alter table student add tizhong decimal(18,1)

--删除一列
alter table student Drop column tizhong
select name as '姓名' from student where age>25
select * from student where age>24

当前时间距离哪一天还剩下多长时间精确到秒

function time()
{

    var date1=new Date();  //开始时间
    var date2=new Date(2016,3,30,0,0,0);    //结束时间
    var date3=date2.getTime()-date1.getTime()  //时间差的毫秒数

//计算出相差天数
var days=Math.floor(date3/(24*3600*1000))

//计算出小时数

var leave1=date3%(24*3600*1000)    //计算天数后剩余的毫秒数
var hours=Math.floor(leave1/(3600*1000))
//计算相差分钟数
var leave2=leave1%(3600*1000)        //计算小时数后剩余的毫秒数
var minutes=Math.floor(leave2/(60*1000))

//计算相差秒数
var leave3=leave2%(60*1000)      //计算分钟数后剩余的毫秒数
var seconds=Math.round(leave3/1000)
    var qqqq=document.getElementById("qqqq");
    qqqq.innerHTML="<font color='#FFFFFF' face='经典粗宋简'>4/30前预订独家方案，再送300元&nbsp;还有</font>"+days+"<font color='#FFFFFF' face='经典粗宋简'>天</font>"+hours+"<font color='#FFFFFF' face='经典粗宋简'>小时<font>"+minutes+"<font color='#FFFFFF' face='经典粗宋简'>分</font>"+seconds+"<font color='#FFFFFF' face='经典粗宋简'>秒</font>";
    window.setTimeout("time()",1000);
}
window.setTimeout("time()",0)