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

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

其他回答

您可以用子查询创建一个逗号分隔的列表,并且后面没有最后一个逗号。据说这比之前使用的函数更有效。我想是2005年之后。

SELECT 
    Project.ProjectName,
    (SELECT
        SUBSTRING(
            (SELECT ', ' + Site.SiteName
            FROM Site
            WHERE Site.ProjectKey = Project.ProjectKey
            ORDER BY Project.ProjectName
    FOR XML PATH('')),2,200000)) AS CSV 
FROM Project

您还可以使用带有嵌套查询的FOR XML PATH来选择XML,我发现这很有用。

HashBytes()返回其输入的MD2、MD4、MD5、SHA或SHA1哈希值。

这是我今天学到的一个,因为我需要搜索一笔交易。

:: fn_dblog 这允许您查询数据库的事务日志。

USE mydatabase;
SELECT *
FROM ::fn_dblog(NULL, NULL)

http://killspid.blogspot.com/2006/07/using-fndblog.html

存储过程的一个技巧是可以从INSERT语句调用它们。当我在SQL Server数据库上工作时,我发现这非常有用。

CREATE TABLE #toto (v1 int, v2 int, v3 char(4), status char(6))
INSERT #toto (v1, v2, v3, status) EXEC dbo.sp_fulubulu(sp_param1)
SELECT * FROM #toto
DROP TABLE #toto

我最喜欢master..xp_cmdshell。它允许您从服务器上的命令提示符运行命令并查看输出。如果你不能登录到服务器,但你需要获取信息或以某种方式控制它,它是非常有用的。

例如,列出运行SQL server的服务器C:驱动器上的文件夹。

主. .Xp_cmdshell ` dir c:\ `

您还可以启动和停止服务。

主. .xp_cmdshell的sc查询“My . 服务”的 主. .xp_cmdshell 'sc stop“My . 服务”的 主. .xp_cmdshell 'sc start“My . 服务”的

它很强大,但也有安全隐患。许多人禁用它,因为它很容易被用来在服务器上做坏事。但是,如果你能接触到它,它会非常有用。