问从select查询存储过程将nvarchar转换为int数据类型

EN

USE [SLCBRegistrarDB]
 GO
 /****** Object:  StoredProcedure [dbo].[CountLabfees]    Script Date: 
 10/30/2017 7:06:43 PM ******/
 SET ANSI_NULLS ON
 GO
 SET QUOTED_IDENTIFIER ON
 GO
 ALTER Procedure [dbo].[CountLabfees]
 @LabSubject nvarchar(50)

 as

 BEGIN
 SET NOCOUNT ON;
 Declare @SQL NVARCHAr(MAX)
 SET @LabSubject = REPLACE(@LabSubject,',',''',''')
 SET @SQL='SELECT Distinct(TESTFeeSETUP.[Fee Code])
 FROM TESTFeeSETUP INNER JOIN TESTFeeSETUPSubTable ON TESTFeeSETUP.[Fee 
 Specification] = TESTFeeSETUPSubTable.[Specification ID]
 WHERE TESTFeeSETUPSubTable.Specification in (''' + @LabSubject + ''')'

 Declare @Quantity NVARCHAr(MAX)
 SET @Quantity='SELECT Count(FEESList.[Fee Description]) AS Quantity
 FROM FEESList INNER JOIN TESTFeeSETUP ON FEESList.FeeID = 
 TESTFeeSETUP.FeeID INNER JOIN TESTFeeSETUPSubTable ON TESTFeeSETUP.[Fee 
 Specification] = TESTFeeSETUPSubTable.[Specification ID]
 WHERE TESTFeeSETUPSubTable.Specification in (''' + @LabSubject + ''')'

 Declare @Total NVARCHAr(MAX)
 SET @Total='SELECT Distinct(TESTFeeSETUP.[Amount/Cost])
 FROM TESTFeeSETUP INNER JOIN TESTFeeSETUPSubTable ON TESTFeeSETUP.[Fee 
 Specification] = TESTFeeSETUPSubTable.[Specification ID]
 WHERE TESTFeeSETUPSubTable.Specification in (''' + @LabSubject + ''')'

 EXEC (@SQL)
 EXEC (@Total)
 EXEC (@Quantity)
 END
 BEGIN
    INSERT INTO FeesStudentBILLING VALUES(10,@SQL,@Quantity,@Total,1,1)
 END