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

我知道它并不是完全隐藏的,但是没有太多人知道PIVOT命令。我能够改变一个使用游标的存储过程,并花费2分钟来运行一段6秒的代码,而这段代码的行数是原来的十分之一!

其他回答

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/

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

这里有一些未记录的命令:未记录但很方便的SQL server Procs和DBCC命令

这里有一个简单但有用的例子:

手动编辑表内容时,可以通过输入Control-0在列中插入NULL。

找出最流行的查询

与系统。Dm_exec_query_stats,您可以通过一个查询计算出许多查询分析的组合。

链接 用命令

select * from sys.dm_exec_query_stats 
order by execution_count desc