资源 地址
Microsoft 产品支持服务 Web 站点 http://support.microsoft.com/directory
Microsoft Usenet news://msnews.microsoft.com/
Microsoft Windows® 硬件兼容性列表 http://www.microsoft.com/hcl
MSDN® http://msdn.microsoft.com
Meta Data Services(即以前的 Microsoft 知识库) http://msdn.microsoft.com
SQL Server 专业协会 http://www.sqlpass.org/
Microsoft SQL Server 开发人员中心 http://msdn.microsoft.com
SQL Server 杂志 http://www.sqlmag.com/
Microsoft SQL Server 技术支持 http://support.microsoft.com/support/sql
TechNet 站点 http://www.Microsoft.com/technet
Microsoft 辅助工具 Web 站点 http://www.microsoft.com/enable
Microsoft SQL Server Web 站点 http://www.microsoft.com/sql
Microsoft SQL Server Web 站点上的 English Query 页 http://www.microsoft.com/sql
Microsoft SQL Server Web 站点上的 Analysis Services 页 http://www.microsoft.com/sql
XML 开发人员中心 http://www.msdn.microsoft.com/xml/default.asp
Microsoft 产品支持服务 Web 站点 http://support.microsoft.com/directory
Microsoft Usenet news://msnews.microsoft.com/
Microsoft Windows® 硬件兼容性列表 http://www.microsoft.com/hcl
MSDN® http://msdn.microsoft.com
Meta Data Services(即以前的 Microsoft 知识库) http://msdn.microsoft.com
SQL Server 专业协会 http://www.sqlpass.org/
Microsoft SQL Server 开发人员中心 http://msdn.microsoft.com
SQL Server 杂志 http://www.sqlmag.com/
Microsoft SQL Server 技术支持 http://support.microsoft.com/support/sql
TechNet 站点 http://www.Microsoft.com/technet
Microsoft 辅助工具 Web 站点 http://www.microsoft.com/enable
Microsoft SQL Server Web 站点 http://www.microsoft.com/sql
Microsoft SQL Server Web 站点上的 English Query 页 http://www.microsoft.com/sql
Microsoft SQL Server Web 站点上的 Analysis Services 页 http://www.microsoft.com/sql
XML 开发人员中心 http://www.msdn.microsoft.com/xml/default.asp
关系运算:并运算
select c1,c2 from t1
union all
select c1,c2 from t2差:
c1-c2:select * from t1 where not exists(select 1 from t2 where t1.c1=t2.c1 and t1.c2=t2.c2)c2-c1:select * from t2 where not exists(select 1 from t1 where t1.c1=t2.c1 and t1.c2=t2.c2)交:
select * from t1 where exists(select 1 from t2 where t1.c1=t2.c1 and t1.c2=t2.c2)
除:
create table #1(A char(1),B char(1),C char(1),D char(1))
insert #1 values('a','b','c','d')
insert #1 values('a','b','e','f')
insert #1 values('b','c','e','f')
insert #1 values('e','d','c','d')
insert #1 values('e','d','e','f')
insert #1 values('a','b','d','e')create table #2 (A char(1),B char(1))
insert #2 values('c','d')
insert #2 values('e','f')select a,b from #1 bb where exists(select 1 from (select distinct #1.a,#1.b,#2.a c,#2.b d from #1,#2) aa where aa.a=bb.a and aa.b=bb.b and aa.c=bb.c and aa.d=bb.d) group by a,b having count(*)>1用left join来着差运算create table #a(a int,b int)
create table #b(a int,b int)
insert #a values(1,1)
insert #a values(2,2)
insert #b values(1,1)
insert #b values(3,3)#a-#b
select a.*
from #a a left join #b b on a.a=b.a and a.b=b.b
where b.a is null#b-#a
select b.*
from #b b left join #a a on a.a=b.a and a.b=b.b
where a.a is nullor:
select b.*
from #a a right join #b b on a.a=b.a and a.b=b.b
where a.a is null
select c1,c2 from t1
union all
select c1,c2 from t2差:
c1-c2:select * from t1 where not exists(select 1 from t2 where t1.c1=t2.c1 and t1.c2=t2.c2)c2-c1:select * from t2 where not exists(select 1 from t1 where t1.c1=t2.c1 and t1.c2=t2.c2)交:
select * from t1 where exists(select 1 from t2 where t1.c1=t2.c1 and t1.c2=t2.c2)
除:
create table #1(A char(1),B char(1),C char(1),D char(1))
insert #1 values('a','b','c','d')
insert #1 values('a','b','e','f')
insert #1 values('b','c','e','f')
insert #1 values('e','d','c','d')
insert #1 values('e','d','e','f')
insert #1 values('a','b','d','e')create table #2 (A char(1),B char(1))
insert #2 values('c','d')
insert #2 values('e','f')select a,b from #1 bb where exists(select 1 from (select distinct #1.a,#1.b,#2.a c,#2.b d from #1,#2) aa where aa.a=bb.a and aa.b=bb.b and aa.c=bb.c and aa.d=bb.d) group by a,b having count(*)>1用left join来着差运算create table #a(a int,b int)
create table #b(a int,b int)
insert #a values(1,1)
insert #a values(2,2)
insert #b values(1,1)
insert #b values(3,3)#a-#b
select a.*
from #a a left join #b b on a.a=b.a and a.b=b.b
where b.a is null#b-#a
select b.*
from #b b left join #a a on a.a=b.a and a.b=b.b
where a.a is nullor:
select b.*
from #a a right join #b b on a.a=b.a and a.b=b.b
where a.a is null