存储过程， 生成SQL语句

USE [sfaecrm]
GO
/****** 对象:  StoredProcedure [dbo].[proc_insert]    脚本日期: 05/29/2009 06:16:07 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER proc [dbo].[proc_insert] (@tablename varchar(256))
as
begin
        set nocount on
        declare @sqlstr varchar(4000)
        declare @sqlstr1 varchar(4000)
        declare @sqlstr2 varchar(4000)
        select @sqlstr='select ''insert '+@tablename
        select @sqlstr1=''
        select @sqlstr2=' ('
        select @sqlstr1= ' values ( ''+'
        select @sqlstr1=@sqlstr1+col+'+'',''+' ,@sqlstr2=@sqlstr2+name +',' from (select case
--        when a.xtype =173 then 'case when '+a.name+' is null then ''NULL'' else '+'convert(varchar('+convert(varchar(4),a.length*2+2)+'),'+a.name +')'+' end'
        when a.xtype =127 then 'case when '+a.name+' is null then ''NULL'' else '+'convert(varchar(20),'+a.name +')'+' end'
        when a.xtype =104 then 'case when '+a.name+' is null then ''NULL'' else '+'convert(varchar(1),'+a.name +')'+' end'
        when a.xtype =175 then 'case when '+a.name+' is null then ''NULL'' else '+'''''''''+'+'replace('+a.name+','''''''','''''''''''')' + '+'''''''''+' end'
        when a.xtype =61  then 'case when '+a.name+' is null then ''NULL'' else '+'''''''''+'+'convert(varchar(23),'+a.name +',121)'+ '+'''''''''+' end'
        when a.xtype =106 then 'case when '+a.name+' is null then ''NULL'' else '+'convert(varchar(