关于group by,该怎么处理

关于group by

SQL code

if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[TB_Student]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)drop table [dbo].[TB_Student]GOCREATE TABLE [dbo].[TB_Student] (    [strStudent] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NOT NULL ,    [strClass] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NOT NULL ,    [nScore] [int] NOT NULL ) ON [PRIMARY]GOinsert into TB_Student(strStudent,strClass,nScore) values('张三','语文',65)insert into TB_Student(strStudent,strClass,nScore) values('张三','数学',85)insert into TB_Student(strStudent,strClass,nScore) values('张三','英语',90)insert into TB_Student(strStudent,strClass,nScore) values('李四','语文',56)insert into TB_Student(strStudent,strClass,nScore) values('李四','数学',67)insert into TB_Student(strStudent,strClass,nScore) values('李四','英语',89)insert into TB_Student(strStudent,strClass,nScore) values('王五','语文',56)insert into TB_Student(strStudent,strClass,nScore) values('王五','数学',55)insert into TB_Student(strStudent,strClass,nScore) values('王五','英语',87)/*结果 姓名   学科   成绩'张三','英语',90'李四','英语',89'王五','英语',87*/--谢谢 各位

SQL code

select * from TB_Student twhere not exists(select 1 from TB_Student where strStudent=t.strStudent and nScore>t.nScore)
[解决办法]
  
为什么不直接用

select * from dbo.TB_Student  where strclass='英语'
[解决办法]
貌似和group by 没有关系

SQL code
select * from [TB_Student] where strClass='英语'
[解决办法]
SQL code
select * from TB_Student awhere nScore=(select max(nScore) from TB_Student where strStudent=a.strStudent)