SqlSever基础 group by之后，加having 对分组之后的数据在进行处理

 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teacher
14 create table Teacher
15 (
16    Id int primary key identity(1,1),   
17    Name nvarchar(10),
18    Class nchar(2),
19    score float
20 )
21 
22 create table Location
23 (
24    Class nchar(2),
25    location nvarchar(5)
26 )
27 
28 --看看 teacher这个表格有啥
29 select * from Teacher
30 select * from Location
31 
32 --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
33 insert into Teacher
34        values(‘燃灯古佛‘,‘佛家‘,100),
35              (‘释迦摩尼佛‘,‘佛家‘,100),
36              (‘弥勒佛‘,‘佛家‘,100),
37              (‘释迦摩尼佛‘,‘佛家‘,100),
38              (‘女娲娘娘‘,‘道家‘,100),
39              (‘文殊菩萨‘,‘佛家‘,100),
40              (‘普贤菩萨‘,‘佛家‘,101), --为了方便，给普贤菩萨加1分
41              (‘阳明贪狼太星君‘,‘道家‘,101),
42              (‘阴精巨门元星君‘,‘道家‘,101),
43              (‘真人禄存真星君‘,‘道家‘,101),
44              (‘玄冥文曲纽星君‘,‘道家‘,101)
45 
46 --向这个Location中插入这几行内容
47 insert into Location
48         values(‘佛家‘,‘印度‘),
49               (‘道家‘,‘中国‘),
50               (‘基督‘,‘西方‘),
51               (‘儒家‘,‘中国‘)
52 
53 --查看teacher表中有什么内容
54 select * from Teacher
55 
56 
57 select Class,score,count(*) as num
58 from Teacher
59 where score=100
60 group by Class,score

1 select Class,score,count(*) as num
2 from Teacher
3 where score=100
4 group by Class,score

1 --求取在teacher表中，存的，佛道两家 获得 100的 ，且 大于2的
2 --as起的别名在having后面用不上的，只能按照count(*)去做
3 select Class,score,count(*) as num
4 from Teacher
5 where score=100
6 group by Class,score having count(*)>2