sql根据传入参数确定选择前几条数据的存储过程

USE [BeijingAgricultureDB]
GO
DECLARE	@return_value int
EXEC	@return_value = [dbo].[SelectTopNNotifications]
@num = 2
SELECT	'Return Value' = @return_value
GO

/* Show not having access to variables from the calling batch. */
DECLARE @CharVariable CHAR(3)
SET @CharVariable = 'abc'
/* sp_executesql fails because @CharVariable has gone out of scope. */
sp_executesql N'PRINT @CharVariable'
GO
/* Show database context resetting after sp_executesql completes. */
USE pubs
GO
sp_executesql N'USE Northwind'
GO
/* This statement fails because the database context
has now returned to pubs. */
SELECT * FROM Shippers
GO

DECLARE @IntVariable INT
DECLARE @SQLString NVARCHAR(500)
/* Build and execute a string with one parameter value. */
SET @IntVariable = 35
SET @SQLString = N'SELECT * FROM pubs.dbo.employee WHERE job_lvl = ' +
CAST(@IntVariable AS NVARCHAR(10))
EXEC(@SQLString)
/* Build and execute a string with a second parameter value. */
SET @IntVariable = 201
SET @SQLString = N'SELECT * FROM pubs.dbo.employee WHERE job_lvl = ' +
CAST(@IntVariable AS NVARCHAR(10))
EXEC(@SQLString)

DECLARE @IntVariable INT
DECLARE @SQLString NVARCHAR(500)
DECLARE @ParmDefinition NVARCHAR(500)
/* Build the SQL string once. */
SET @SQLString =
N'SELECT * FROM pubs.dbo.employee WHERE job_lvl = @level'
/* Specify the parameter format once. */
SET @ParmDefinition = N'@level tinyint'
/* Execute the string with the first parameter value. */
SET @IntVariable = 35
EXECUTE sp_executesql @SQLString, @ParmDefinition,
@level = @IntVariable
/* Execute the same string with the second parameter value. */
SET @IntVariable = 32
EXECUTE sp_executesql @SQLString, @ParmDefinition,
@level = @IntVariable