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
好吧，这是我的观点:
http://dbalink.wordpress.com/2008/10/24/querying-the-object-catalog-and-information-schema-views/
我懒得在这里重新写一遍，所以请查看我的帖子。这对许多人来说可能是微不足道的，但会有一些人会发现它是一颗“隐藏的宝石”。
编辑:
过了一会儿，我决定在这里添加代码，这样您就不必跳转到我的博客来查看代码了。
SELECT T.NAME AS [TABLE NAME], C.NAME AS [COLUMN NAME], P.NAME AS [DATA TYPE], P.MAX_LENGTH AS[SIZE], CAST(P.PRECISION AS VARCHAR) +‘/’+ CAST(P.SCALE AS VARCHAR) AS [PRECISION/SCALE]
FROM ADVENTUREWORKS.SYS.OBJECTS AS T
JOIN ADVENTUREWORKS.SYS.COLUMNS AS C
ON T.OBJECT_ID=C.OBJECT_ID
JOIN ADVENTUREWORKS.SYS.TYPES AS P
ON C.SYSTEM_TYPE_ID=P.SYSTEM_TYPE_ID
WHERE T.TYPE_DESC=‘USER_TABLE’;
或者，如果你想拉出所有的用户表，像这样使用CURSOR:
DECLARE @tablename VARCHAR(60)
DECLARE cursor_tablenames CURSOR FOR
SELECT name FROM AdventureWorks.sys.tables
OPEN cursor_tablenames
FETCH NEXT FROM cursor_tablenames INTO @tablename
WHILE @@FETCH_STATUS = 0
BEGIN
SELECT t.name AS [TABLE Name], c.name AS [COLUMN Name], p.name AS [DATA Type], p.max_length AS[SIZE], CAST(p.PRECISION AS VARCHAR) +‘/’+ CAST(p.scale AS VARCHAR) AS [PRECISION/Scale]
FROM AdventureWorks.sys.objects AS t
JOIN AdventureWorks.sys.columns AS c
ON t.OBJECT_ID=c.OBJECT_ID
JOIN AdventureWorks.sys.types AS p
ON c.system_type_id=p.system_type_id
WHERE t.name = @tablename
AND t.type_desc=‘USER_TABLE’
ORDER BY t.name ASC
FETCH NEXT FROM cursor_tablenames INTO @tablename
END
CLOSE cursor_tablenames
DEALLOCATE cursor_tablenames
其他参考资料(我的博客):http://dbalink.wordpress.com/2009/01/21/how-to-create-cursor-in-tsql/
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。
