use db_CSharp
go
 select *,
 备注=case 
 when Grade>=90 then '成绩优秀'
 when Grade<90 and Grade>=80 then '成绩良好'
 when Grade<80 and Grade>=70 then '成绩及格'
 else '不及格'
 end 
 from tb_Grade

select * from sysobjects where id=a
select getdate()

select * from sysobjects where id=a
go
select getdate()
go

use master
go

if exists (select * from sysdatabases where name = 'kejianDB')
drop database kejianDB
go

create database kejianDB
go

use kejianDB
go


--(行业表)
create table Trade
(
tra_Id int primary key identity(1,1) not null, --行业ID (主键、自增长)
tra_Name varchar(50) not null --行业名称
)
go