select * from tdx_order t inner join [Tdx_Safety] s on t.id = s.[OrderId]
- ---
- if exists(select [id] from sysobjects where name='student')
- drop table student
- go
-
- create table student
- (
- sname varchar(20) not null,
- sclass varchar(20) not null
- )
- go
-
- alter table student add constraint pk_student primary key(sname,sclass);
- go
-
- if exists(select [id] from sysobjects where name='score')
- drop table score
- go
-
- create table score
- (
- scoreid int not null primary key identity(1,1),
- sname varchar(20) not null,
- sclass varchar(20) not null,
- score float
- )
- go
-
- alter table score add constraint fk_score foreign key(sname,sclass) references student(sname,sclass);
- go
-
- insert into student values('aaa','1');
- insert into student values('ccc','2');
- insert into student values('bbb','2');
- insert into student values('ddd','2');
- insert into student values('ccc','3');
- insert into student values('ddd','4');
-
- insert into score(sname,sclass,score) values('aaa',1,66);
- insert into score(sname,sclass,score) values('bbb',2,77);
- insert into score(sname,sclass,score) values('ccc',2,88);
- insert into score(sname,sclass,score) values('ddd',4,99);
-
- /*
- --外键插入null值
- insert into score(score) values(66);
- insert into score(score) values(77);
- insert into score(score) values(77);
- */
-
- select * from student;
- select * from score;
-
- --复合主键内连接
- select * from student t inner join score s on t.sname = s.sname and t.sclass = s.sclass;
-
- --复合主键左外连接
- select t.sname,t.sclass from student t left outer join score s on t.sname = s.sname and t.sc
posted @
2008-10-28 12:40
window5549-accp
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