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
dm_db_index_usage_stats
这允许您知道表中的数据最近是否更新过，即使表上没有DateUpdated列。
SELECT OBJECT_NAME(OBJECT_ID) AS DatabaseName, last_user_update,*
FROM sys.dm_db_index_usage_stats
WHERE database_id = DB_ID( 'MyDatabase')
AND OBJECT_ID=OBJECT_ID('MyTable')
代码来自:http://blog.sqlauthority.com/2009/05/09/sql-server-find-last-date-time-updated-for-any-table/
参考资料:
SQL Server -表的最后插入行的日期/时间是什么?
在SQL 2005及更高版本中可用
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/
执行一个存储过程，并在(temp)表中捕获结果，以便进一步处理，例如:
INSERT INTO someTable EXEC sp_someproc
示例:显示sp_help输出，但按数据库大小排序:
CREATE TABLE #dbs
(
name nvarchar(50),
db_size nvarchar(50),
owner nvarchar(50),
dbid int,
created datetime,
status nvarchar(255),
compatiblity_level int
)
INSERT INTO #dbs EXEC sp_helpdb
SELECT * FROM #dbs
ORDER BY CONVERT(decimal, LTRIM(LEFT(db_size, LEN(db_size)-3))) DESC
DROP TABLE #dbs
