SqlSever基础 top 后面的n 由一个简单的计算式子计算得出

 1 use master
 2 drop database helloworld
 3 
 4 
 5 --创建一个数据库
 6 create database helloworld
 7 
 8 
 9 
10 --用helloworld1这个数据库
11 use helloworld
12 
13 --创建一个表格FoJiaTeacher
14 create table FoJiaTeacher
15 (
16    Id int primary key identity(1,1),   
17    Name nvarchar(10),
18    Class nchar(2),
19    score decimal
20 )
21 
22 --创建一个表格FoJiaTeacher
23 create table DaoJiaTeacher
24 (
25    Id int primary key identity(1,1),   
26    Name nvarchar(10),
27    Class nchar(2),
28    score decimal
29 )
30 
31 
32 select * from FoJiaTeacher
33 select * from DaoJiaTeacher
34 
35 --向这个Teacher中插入这几行内容,这个内容我插入一遍后，简单修改，又插入一遍
36 insert into FoJiaTeacher
37        values(‘燃灯古佛‘,‘佛家‘,99),
38              (‘释迦摩尼佛‘,‘佛家‘,100),
39              (‘弥勒佛‘,‘佛家‘,101),
40              (‘释迦摩尼佛‘,‘佛家‘,102),
41              (‘文殊菩萨‘,‘佛家‘,103),
42              (‘普贤菩萨‘,‘佛家‘,104) --为了方便，给普贤菩萨加1分
43 
44 insert into DaoJiaTeacher
45        values(‘女娲娘娘‘,‘道家‘,100),
46              (‘阳明贪狼太星君‘,‘道家‘,101),
47              (‘阴精巨门元星君‘,‘道家‘,101),
48              (‘真人禄存真星君‘,‘道家‘,101),
49              (‘玄冥文曲纽星君‘,‘道家‘,101)
50 
51 select * from FoJiaTeacher order by score desc 
52 select * from DaoJiaTeacher order by score desc 

1 -- top 后面的整数由一个简单的计算式得出时，要写括号
2 --你要是写小数，程序会提示错误的
3 select top (3*1) * from FoJiaTeacher order by score desc 

1 -- 来一个百分比的,我要看道家前百分之50的
2 select top (5*10) percent * from DaoJiaTeacher order by score desc