关于sql语句的疑问

sql2005下，如下sql:

declare @sql varchar(2000)

set @sql='select * from Sysobjects'

exec(@sql)

在此如果不加括号,如（exec @sql），就会提示"找不到存储过程 'select * from Sysobjects'。";

加上括号则可正常执行.

exec执行存储过程或者函数，不用加挎号，否则要加

见 http://msdn.microsoft.com/en-us/library/ms188332.aspx

下面是Exec 的语法

从语法定义可以看出，如果不加挎号， SQL SERVER 就会认为Exec 后面跟的是存储过程或者函数，所以会出现找不到存储过程的错误。

Execute a stored procedure or function

[ { EXEC | EXECUTE } ]

    { 

      [ @return_status = ]

      { module_name [ ;number ] | @module_name_var } 

        [ [ @parameter = ] { value 

                           | @variable [ OUTPUT ] 

                           | [ DEFAULT ] 

                           }

        ]

      [ ,...n ]

      [ WITH RECOMPILE ]

    }

[;]



Execute a character string

{ EXEC | EXECUTE } 

        ( { @string_variable | [ N ]'tsql_string' } [ + ...n ] )

    [ AS { LOGIN | USER } = ' name ' ]

[;]



Execute a pass-through command against a linked server

{ EXEC | EXECUTE }

        ( { @string_variable | [ N ] 'command_string [ ? ] ' } [ + ...n ]

        [ { , { value | @variable [ OUTPUT ] } } [ ...n ] ]

        ) 

    [ AS { LOGIN | USER } = ' name ' ]

    [ AT linked_server_name ]

[;]