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

查找日期落在当前周内的记录。

where dateadd( week, datediff( week, 0, TransDate ), 0 ) =
dateadd( week, datediff( week, 0, getdate() ), 0 )

查找上周发生的日期记录。

where dateadd( week, datediff( week, 0, TransDate ), 0 ) =
dateadd( week, datediff( week, 0, getdate() ) - 1, 0 )

返回当前周的开始日期。

select dateadd( week, datediff( week, 0, getdate() ), 0 )

返回上周开始的日期。

select dateadd( week, datediff( week, 0, getdate() ) - 1, 0 )

2008-09-23 15:55:41

其他回答

use db
go 

select o.name 
, (SELECT [definition] AS [text()] 
     FROM sys.all_sql_modules 
     WHERE sys.all_sql_modules.object_id=a.object_id 
     FOR XML PATH(''), TYPE
  )  AS Statement_Text
 , a.object_id
 , o.modify_date 

 FROM sys.all_sql_modules a 
 LEFT JOIN  sys.objects o ON a.object_id=o.object_id 
 ORDER BY  4 desc

--select * from sys.objects

2009-02-12 20:18:12

许多SQL Server开发人员似乎仍然不知道DELETE、INSERT和UPDATE语句中的OUTPUT子句(SQL Server 2005及更新版本)。

知道哪些行被插入、更新或删除是非常有用的，OUTPUT子句可以很容易地做到这一点——它允许访问称为插入和删除的“虚拟”表(就像在触发器中一样):

DELETE FROM (table)
OUTPUT deleted.ID, deleted.Description
WHERE (condition)

如果你在一个有INT IDENTITY主键字段的表中插入值，使用OUTPUT子句，你可以立即获得插入的新ID:

INSERT INTO MyTable(Field1, Field2)
OUTPUT inserted.ID
VALUES (Value1, Value2)

如果你正在更新，知道发生了什么变化是非常有用的——在这种情况下，插入表示更新之后的新值，而删除则指更新之前的旧值:

UPDATE (table)
SET field1 = value1, field2 = value2
OUTPUT inserted.ID, deleted.field1, inserted.field1
WHERE (condition)

如果将返回大量信息，output的输出也可以重定向到临时表或表变量(output INTO @myInfoTable)。

非常有用——却鲜为人知!

Marc

2009-08-07 09:03:38

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

EXCEPT和INTERSECT

在比较两个查询结果时，这两个关键字是一种更优雅的简写和可读的表达查询意图的方式，而不是编写复杂的连接和子查询。作为SQL Server 2005的新版本，它们有力地补充了在TSQL语言中已经存在多年的UNION。

EXCEPT、INTERSECT和UNION是集合论中的基本概念，集合论是所有现代RDBMS使用的关系建模的基础和基础。现在，使用TSQL可以更直观、更容易地生成维恩图类型的结果。

2008-11-25 19:36:01

本周我学到的最令人惊讶的事情是在ORDER By子句中使用CASE语句。例如:

declare @orderby varchar(10)

set @orderby = 'NAME'

select * 
    from Users
    ORDER BY 
        CASE @orderby
            WHEN 'NAME' THEN LastName
            WHEN 'EMAIL' THEN EmailAddress
        END

2008-11-26 15:43:39

SQL Server的隐藏特性

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