储存过程执行出现的问题
代码如下：

ALTER Procedure [dbo].[ShipDateQtyPush_Plan]

@S		Varchar(10),

@F		Varchar(10),

@FnSam	Varchar(15),

@FnQty	Varchar(15),@Grade	Float

As

Create Table #a

(

	PO			Varchar(20),

	Season		Varchar(10),

	Style		Varchar(20),

	ShipDate	Varchar(10),

	Customer	Varchar(10),

	Color		Varchar(50),

	Qty			Int,

	CuttingQty	Int,

	Qty226		Int,

	Sam			Float,

	ActQty		Int,

	DiffQty		Int

)

Declare @str	Varchar(8000)

Set @str='	Insert into #a

			Select 

				PO,Season,Style,Convert(Varchar(10),ShipDate,120) ShipDate,Customer,Color, 

				Sum(Qty) Qty,Sum(CuttingQty) CuttingQty,Sum(Qty226) Qty226,'+@FnSam+' Sam, 

				Sum('+@FnQty+') ActQty,Sum(Qty-'+@FnQty+') DiffQty

			from 

				ShipDateQtyPush 

			where  

				ShipDate>='''+@S+''' and ShipDate<='''+@F+'''

			Group by

				PO,Season,Style,ShipDate,Customer,Color,Sam331	'

Exec(@str)

--------------------------------------------------------------------

declare @sql varchar(8000)

set @sql='select PO,Season,Style,Customer,ShipDate,Color,Qty,CuttingQty,Qty226,Round(Sam,2) Sam,ActQty'

select @sql=@sql+',['+dd+'ろ计]=sum(case Convert(Varchar(10),ShipDate,120) when '''+dd+''' then DiffQty else 0 end)'

+',['+dd+'惠]=sum(case Convert(Varchar(10),ShipDate,120) when '''+dd+''' then Round((Qty-ActQty)*(Sam'+@Grade+')/60,2) else 0 end)'

from (select distinct dd=Convert(Varchar(10),ShipDate,120) from #a) ss

set @sql=@sql+'  from #a group by PO,Season,Style,Customer,ShipDate,Color,Qty,CuttingQty,Qty226,Sam,ActQty'

exec(@sql)

Drop table #a

执行：
ShipDateQtyPush_Plan 
'2013-06-13',
'2013-06-22',
'Sam331',
'Qty331',
1
然后提示

(58 row(s) affected)
Msg 8114, Level 16, State 5, Procedure ShipDateQtyPush_Plan, Line 38
Error converting data type varchar to float.
我就是加了@Grade这个变量之后出错的，想请问该怎么做？
------解决方案--------------------
可以先把@sql打印出来后到查询分析器中检查语法有没有错误了
------解决方案--------------------

--需要转@Grade为文本才能添加在@sql中



declare @sql varchar(8000)

set @sql='select PO,Season,Style,Customer,ShipDate,Color,Qty,CuttingQty,Qty226,Round(Sam,2) Sam,ActQty'

select @sql=@sql+',['+dd+'ろ计]=sum(case Convert(Varchar(10),ShipDate,120) when '''+dd+''' then DiffQty else 0 end)'

+',['+dd+'惠]=sum(case Convert(Varchar(10),ShipDate,120) when '''+dd+''' then Round((Qty-ActQty)*(Sam'+convert(varchar,@Grade)+')/60,2) else 0 end)' ----这里

from (select distinct dd=Convert(Varchar(10),ShipDate,120) from #a) ss

set @sql=@sql+'  from #a group by PO,Season,Style,Customer,ShipDate,Color,Qty,CuttingQty,Qty226,Sam,ActQty'