动态语句exec与sp_executesql执行计划区别

--測試如下(Windows2003+SQL2005 sp3)

 

USE tempdb

go

IF OBJECT_ID ( 'Test' ) IS NOT NULL

    DROP TABLE Test

SELECT * INTO Test FROM syscolumns

 

go

--step1:

DBCC FREEPROCCACHE -- 清空緩存中的執行計劃

 

--step2:( 執行3次 )

DECLARE @TabName sysname , @ID INT , @SQL NVARCHAR ( 4000)

SET @TabName= 'Test'

SET @ID= 103--@ID{101,102,103} -- 輸入次值，執行3次

SET @SQL= N'SELECT * FROM ' + @TabName+ ' WHERE ID=' + RTRIM ( @ID)+ ' order by ID asc'

EXEC ( @SQL)

-- 查看產執行計劃

SELECT dbName= DB_NAME ( dbID ) , Cacheobjtype, objtype, objid , sql

FROM sys.syscacheobjects WHERE cacheobjtype= 'Compiled Plan'   AND objtype IN( 'Adhoc' , 'prepared' ) AND sql LIKE '%Test%' AND sql NOT LIKE '%syscacheobjects%' AND sql NOT LIKE '%msdb.%'

 

-- 執行計劃產生3次

/*

dbName  Cacheobjtype    objtype objid   sql

tempdb  Compiled Plan   Adhoc   319724907   SELECT * FROM Test WHERE ID=102 order by ID asc

tempdb  Compiled Plan   Adhoc   513201771   SELECT * FROM Test WHERE ID=103 order by ID asc

tempdb  Compiled Plan   Prepared    475976984   (@1 tinyint)SELECT * FROM [Test] WHERE [ID]=@1 ORDER BY [ID] ASC

tempdb  Compiled Plan   Adhoc   674221447   SELECT * FROM Test WHERE ID=101 order by ID asc

*/

go

--step1:

DBCC FREEPROCCACHE -- 清空緩存中的執行計劃

 

--step2:( 執行三次 )

DECLARE @TabName sysname , @ID INT , @SQL NVARCHAR ( 4000)

SET @TabName= 'Test'

SET @ID= 101--@ID{101,102,103} -- 輸入次值，執行三次

SET @SQL= N'SELECT * FROM ' + @TabName+ ' WHERE ID=@ID order by ID asc'

exec sp_executesql @stmt= @SQL, @Params= N'@ID int' , @ID= @ID

SELECT dbName= DB_NAME ( dbID ) , Cacheobjtype, objtype, objid , sql FROM sys.syscacheobjects WHERE cacheobjtype= 'Compiled Plan'   AND objtype IN( 'Adhoc' , 'prepared' ) AND sql LIKE '%Test%' AND sql NOT LIKE '%syscacheobjects%' AND sql NOT LIKE '%msdb.%'

 

-- 執行計劃產生1次

/*

dbName  Cacheobjtype    objtype objid   sql

tempdb  Compiled Plan   Prepared    421211796   (@ID int)SELECT * FROM Test WHERE ID=@ID order by ID asc

*/