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

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

CTRL-E在查询分析器中执行当前选择的文本。

Sp_lock:显示当前所有锁。返回的数据还可以进一步查询:

Spid -与sp_who一起使用它来查看谁拥有锁。

Objid -与select object_name(Objid)一起使用,查看哪个数据库对象被锁定。

删除到数据库的所有连接:

Use Master
Go

Declare @dbname sysname

Set @dbname = 'name of database you want to drop connections from'

Declare @spid int
Select @spid = min(spid) from master.dbo.sysprocesses
where dbid = db_id(@dbname)
While @spid Is Not Null
Begin
        Execute ('Kill ' + @spid)
        Select @spid = min(spid) from master.dbo.sysprocesses
        where dbid = db_id(@dbname) and spid > @spid
End

SQL Server 2005:

select * from sys.dm_os_performance_counters

select * from sys.dm_exec_requests