SQL Server的隐藏特性

SQL Server有哪些隐藏特性?

例如，没有文档的系统存储过程，做一些非常有用但没有足够文档的事情的技巧?

答案

感谢大家的精彩回答!

存储过程

sp_msforeachtable: Runs a command with '?' replaced with each table name (v6.5 and up) sp_msforeachdb: Runs a command with '?' replaced with each database name (v7 and up) sp_who2: just like sp_who, but with a lot more info for troubleshooting blocks (v7 and up) sp_helptext: If you want the code of a stored procedure, view & UDF sp_tables: return a list of all tables and views of database in scope. sp_stored_procedures: return a list of all stored procedures xp_sscanf: Reads data from the string into the argument locations specified by each format argument. xp_fixeddrives:: Find the fixed drive with largest free space sp_help: If you want to know the table structure, indexes and constraints of a table. Also views and UDFs. Shortcut is Alt+F1

片段

Returning rows in random order All database User Objects by Last Modified Date Return Date Only Find records which date falls somewhere inside the current week. Find records which date occurred last week. Returns the date for the beginning of the current week. Returns the date for the beginning of last week. See the text of a procedure that has been deployed to a server Drop all connections to the database Table Checksum Row Checksum Drop all the procedures in a database Re-map the login Ids correctly after restore Call Stored Procedures from an INSERT statement Find Procedures By Keyword Drop all the procedures in a database Query the transaction log for a database programmatically.

功能

哈希字节（） EncryptByKey 枢轴命令

Misc

Connection String extras TableDiff.exe Triggers for Logon Events (New in Service Pack 2) Boosting performance with persisted-computed-columns (pcc). DEFAULT_SCHEMA setting in sys.database_principles Forced Parameterization Vardecimal Storage Format Figuring out the most popular queries in seconds Scalable Shared Databases Table/Stored Procedure Filter feature in SQL Management Studio Trace flags Number after a GO repeats the batch Security using schemas Encryption using built in encryption functions, views and base tables with triggers

当前回答

Sql 2000 + DBCC DROPCLEANBUFFERS:清除缓冲区。当缓冲区是干净的时，用于测试查询的速度。

2009-12-18 14:23:58

其他回答

根据单个语句中管道分隔的id字符串返回结果(替代传递xml或首先将分隔的字符串转换为表)

例子:

DECLARE @nvcIDs nvarchar(max)
SET @nvcIDs = '|1|2|3|'

SELECT C.*
FROM tblCompany C
WHERE @nvcIDs LIKE '%|' + CAST(C.CompanyID as nvarchar) + '|%'

2009-05-21 18:17:19

用于解析存储过程参数:xp_sscanf

将数据从字符串读入每个格式参数指定的参数位置。下面的示例使用xp_sscanf 从源中提取两个值属性中的位置源字符串的格式。

DECLARE @filename varchar (20), @message varchar (20)
EXEC xp_sscanf 'sync -b -fproducts10.tmp -rrandom', 'sync -b -f%s -r%s', 
  @filename OUTPUT, @message OUTPUT
SELECT @filename, @message

这是结果集。

-------------------- -------------------- 
products10.tmp        random

2008-09-23 14:47:43

在SQL Server 2005中，您不再需要运行sp-blocker-pss80存储过程。相反，你可以这样做:

exec sp_configure 'show advanced options', 1;
reconfigure;
go
exec sp_configure 'blocked process threshold', 30;
reconfigure;

然后，您可以启动SQL跟踪，并在“错误和警告”组中选择“阻塞”流程报告事件类。详情请点击这里。

2008-11-25 19:57:47

Vardecimal存储格式

SQL Server 2005为数字和十进制数据类型添加了一种新的存储格式，称为vardecimal。Vardecimal是十进制类型的一种变长表示，可以在行的每个实例中保存未使用的字节。如果十进制定义很大(如decimal(38,6))，但存储的值很小(如0.0)，或者有大量重复值，或者数据填充稀疏，则可以节省最多的时间。

Link

2008-09-29 17:02:46

Stored proc sp_MSdependencies以一种比sp_depends更有用的方式告诉您对象依赖关系。对于某些产品版本，可以方便地暂时禁用子表约束，应用更改然后重新启用子表约束。这是查找依赖于父表的对象的好方法。

这段代码禁用了子表约束:

create table #deps
( oType int,
  oObjName sysname,
  oOwner nvarchar(200),
  oSequence int
)

insert into #deps  
exec sp_MSdependencies @tableName, null, 1315327

exec sp_MSforeachtable @command1 = 'ALTER TABLE ? NOCHECK CONSTRAINT ALL',
@whereand = ' and o.name in (select oObjName from #deps where oType = 8)'

应用更改后，可以运行以下代码重新启用约束:

exec sp_MSforeachtable @command1 = 'ALTER TABLE ? WITH CHECK CHECK CONSTRAINT ALL',
@whereand = ' and o.name in (select oObjName from #deps where oType = 8)'

第三个参数是@flags，它控制列出的依赖项类型。请阅读proc内容，了解如何根据自己的目的更改@flags。该过程使用位掩码来破译您想要返回的内容。

2010-07-20 14:46:19

SQL Server的隐藏特性

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