提取每个分类前n条记录
SELECT ID, Name, CategoryID
FROM TableName AS a
WHERE (ID IN
(SELECT TOP (n) ID
FROM TableName AS b
WHERE (a.CategoryID = CategoryID)))
0、更改数据库的路径
Go
ALTER DATABASE tempdb MODIFY FILE (NAME = tempdev, FILENAME = ' T:\tempdb.mdf ' )
Go
ALTER DATABASE tempdb MODIFY FILE (NAME = templog, FILENAME = ' T:\templog.ldf ' )
Go
1、清除数据库的日志
backup
log
HBS_Dongcheng
with
no_log
go
dbcc
shrinkdatabase (HBS_Dongcheng)
go
2、清除表里面的数据，不计入日志，自增字段复位
truncate
table
TableName
3、允许将显式值插入表的标识列中。
SET
IDENTITY_INSERT
[
database.[ owner.
]
] {
table
} {
ON
|
OFF
}
SET
IDENTITY_INSERT
products
ON
4、SET NOCOUNT { ON | OFF }
当 SET NOCOUNT 为 ON 时，不返回计数（表示受 Transact-SQL 语句影响的行数）。当 SET NOCOUNT 为 OFF 时，返回计数。
疑问：还计数不？只是不返回数值吗？
5、清空SQL Server 的缓存，一般用于测试。
从缓存中清空所有数据
DBCC DROPCLEANBUFFERS
从过程高速缓存中删除所有元素。清空执行计划
DBCC FREEPROCCACHE
6、sys.syscacheobjects系统视图
可以查看 sql语句的执行分析情况。
性能计数器SQL Server:Buffer Manager\Buffer Cache hit ratio来观察缓存命中率
（cpu方面需要关注三个性能计数器：SQLServer:SQL Statistics\Batch Requests/Sec、SQLServer:SQL Statistics\SQLCompilations/sec、SQLServer:SQL Statistics\SQL Re-Compilations/sec。如果compilations数目超过batch请求数目的百分之10，或者recompilations数目超过compilations数目的百分之10，那基本可以说明cpu消耗了太多在编译查询计划上面。
）
R:232
G:234
U:223
我感觉背景色设置成这样挺舒服的。
在IE里不直接打开文件的方法。
7、拦截按键地方法。
document.onkeydown=mykeydown;
23
function mykeydown()
24
{
25 if(event.keyCode==116) //屏蔽F5刷新键
26 {
27 window.event.keyCode=0;
28 return false;
29
}
30 }
最小化、最大化、关闭窗口
<object id=hh1 classid="clsid:ADB880A6-D8FF-11CF-9377-00AA003B7A11">
<param name="Command" value="Minimize"></object>
<object id=hh2 classid="clsid:ADB880A6-D8FF-11CF-9377-00AA003B7A11">
<param name="Command" value="Maximize"></object>
<OBJECT id=hh3 classid="clsid:adb880a6-d8ff-11cf-9377-00aa003b7a11">
<PARAM NAME="Command" VALUE="Close"></OBJECT>
<input type=button value=最小化 onclick=hh1.Click()>
<input type=button value=最大化 onclick=hh2.Click()>
<input type=button value=关闭 onclick=hh3.Click()>
13. 取得控件的绝对位置
//Javascript
<script language="Javascript">
function getIE(e){
var t=e.offsetTop;
var l=e.offsetLeft;
while(e=e.offsetParent)
alert("top="+t+"/nleft="+l);
}
</script>
22.不要滚动条?
让竖条没有:
<body style="overflow:scroll;overflow-y:hidden">
</body>
让横条没有:
<body style="overflow:scroll;overflow-x:hidden">
</body>
两个都去掉？更简单了
<body scroll="no">
</body>
27.在页面中如何加入不是满铺的背景图片,拉动页面时背景图不动
<STYLE>
body
{background-image:url(/blog/logo.gif); background-repeat:no-repeat;
background-position:center;background-attachment: fixed}
</STYLE>
34.脚本永不出错
<SCRIPT LANGUAGE="JavaScript">
<!-- Hide
function killErrors() {
return true;
}
window.onerror = killErrors;
// -->
</SCRIPT>
最大化窗口？
<script language="JavaScript">
<!--
self.moveTo(0,0)
self.resizeTo(screen.availWidth,screen.availHeight)
//-->
</script>
SET STATISTICS IO ON
查看执行的一些参数。
删除字段：http://topic.csdn.net/t/20050607/17/4066163.html
if
exists
(
select
*
from
dbo.sysobjects
where
id
=
object_id
(N
'
[dbo].[p_deletefield]
'
)
and
OBJECTPROPERTY
(id, N
'
IsProcedure
'
)
=
1
)
drop
procedure
[
dbo
]
.
[
p_deletefield
]
GO
/*--删除某字段的所有关系及该字段 删除某字段时,常常因为在该字段上定义了约束/外键/默认值 导致字段删除失败,此存储过就是删除表中指定字段的这些关系 修正2004.05发布的删除处理中的错误,同时改原来的处理语句为通用存储过程 
--邹建 2004.07(引用请保留此信息)--*/
/*--调用示例 exec p_deletefield '表名','字段名' --*/
create
proc
p_deletefield
@tbname
sysname,
--
要处理的表名
@fdname
sysname,
--
要处理的字段名
@delfield
bit
=
1
--
0只删除关系,1同时删除字段
as
declare
hCForEach
cursor
global
for
--
默认值约束
select
sql
=
'
alter table [
'
+
b.name
+
'
] drop constraint [
'
+
d.name
+
'
]
'
from
syscolumns a
join
sysobjects b
on
a.id
=
b.id
and
a.name
=
@fdname
and
b.name
=
@tbname
join
syscomments c
on
a.cdefault
=
c.id
join
sysobjects d
on
c.id
=
d.id
union
--
外键引用
select
s
=
'
alter table [
'
+
c.name
+
'
] drop constraint [
'
+
b.name
+
'
]
'
from
sysforeignkeys a
join
sysobjects b
on
b.id
=
a.constid
join
sysobjects c
on
c.id
=
a.fkeyid
join
syscolumns d
on
d.id
=
c.id
and
a.fkey
=
d.colid
and
d.name
=
@fdname
join
sysobjects e
on
e.id
=
a.rkeyid
and
e.name
=
@tbname
join
syscolumns f
on
f.id
=
e.id
and
a.rkey
=
f.colid
union
--
主键/唯一键/索引
select
case
when
e.xtype
in
(
'
PK
'
,
'
UQ
'
)
then
'
alter table [
'
+
c.name
+
'
] drop constraint [
'
+
e.name
+
'
]
'
else
'
drop index [
'
+
c.name
+
'
].[
'
+
a.name
+
'
]
'
end
from
sysindexes a
join
sysindexkeys b
on
a.id
=
b.id
and
a.indid
=
b.indid
join
sysobjects c
on
b.id
=
c.id
and
c.xtype
=
'
U
'
and
c.name
=
@tbname
join
syscolumns d
on
b.id
=
d.id
and
b.colid
=
d.colid
and
d.name
=
@fdname
left
join
sysobjects e
on
e.id
=
object_id
(a.name)
where
a.indid
not
in
(
0
,
255
)
exec
sp_msforeach_worker
'
?
'
if
@delfield
=
1
exec
(
'
alter table [
'
+
@tbname
+
'
] drop column [
'
+
@fdname
+
'
]
'
)
go
