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

使用GETDATE() +或-来计算附近的日期

SELECT GETDATE() - 1 -- yesterday, 1 day ago, 24 hours ago
SELECT GETDATE() - .5 -- 12 hours ago
SELECT GETDATE() - .25 -- 6 hours ago
SELECT GETDATE() - (1 / 24.0) -- 1 hour ago (implicit decimal result after division)

2011-07-14 21:21:39

其他回答

表校验和

Select CheckSum_Agg(Binary_CheckSum(*)) From Table With (NOLOCK)

行校验和

Select CheckSum_Agg(Binary_CheckSum(*)) From Table With (NOLOCK) Where Column = Value

2008-09-23 15:56:53

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

use db
go      
DECLARE @procName varchar(100)      
DECLARE @cursorProcNames CURSOR      
SET @cursorProcNames = CURSOR FOR      
select name from sys.procedures where modify_date > '2009-02-05 13:12:15.273' order by modify_date desc     

OPEN @cursorProcNames      
FETCH NEXT      
FROM @cursorProcNames INTO @procName      
WHILE @@FETCH_STATUS = 0      
BEGIN      
-- see the text of the last stored procedures modified on 
-- the db , hint Ctrl + T would give you the procedures test 
set nocount off;      
exec sp_HelpText @procName --- or print them      
-- print @procName      

FETCH NEXT      
FROM @cursorProcNames INTO @procName      
END      
CLOSE @cursorProcNames      

select @@error

2009-02-12 19:42:08

仅限返回日期

Select Cast(Floor(Cast(Getdate() As Float))As Datetime)

Select DateAdd(Day, 0, DateDiff(Day, 0, Getdate()))

2008-09-23 15:54:23

Persisted-computed-columns

计算列可以帮助您将运行时计算成本转移到数据修改阶段。计算列与行其余部分一起存储，当计算列上的表达式与查询匹配时，将透明地使用它。您还可以在PCC上构建索引，以加快表达式的过滤和范围扫描。

Link

2008-09-29 17:00:54

SQL Server的隐藏特性

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