建立表：

SET ANSI_NULLS ONGOSET QUOTED_IDENTIFIER ONGOSET ANSI_PADDING ONGOCREATE TABLE [dbo].[stuscore]

( [name] [varchar](50) COLLATE Chinese_PRC_CI_AS NULL,

[subject] [varchar](50) COLLATE Chinese_PRC_CI_AS NULL,

[score] [int] NULL,

[stuid] [int] NULL)

ON [PRIMARY]

GO

SET ANSI_PADDING OFF

插入資料：

insert into dbo.stuscore values ("張三","數學",89,1)；

insert into dbo.stuscore values ("張三","語文",80,1)；

insert into dbo.stuscore values ("張三","英語",70,1)；

insert into dbo.stuscore values ("李四","數學",90,2)；

insert into dbo.stuscore values ("李四","語文",70,2)；

insert into dbo.stuscore values ("李四","英語",80,2)；

查詢結果如下：

列出各門課程的平均成績：

select subject,AVG(score)平均成績 from stuscore

group by subject;