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【DM版本】: 8
【操作系统】：win
【CPU】: Intel
【问题描述】*：

create or replace function f_decodepay(f in number) 
return number
as
	v_key varchar(50); 
	v_t varchar(1000); -- 结果数字
	v_ft varchar(1000); -- 需要解密的数字的字符串
	v_c varchar(1);
	v_temp number;
	v_temp2 number;
	v_i2 integer;
	v_flag varchar(1);
	v_ft_length integer;
	v_i integer;
begin

	v_key:='384962867' ; -- from b2x701nk  by:	String secretNumKey = String.valueOf(java.lang.Math.abs("b2x701nk".hashCode()));
	
	v_t := '';
	v_ft := convert(varchar , f);
	v_flag := case when substr(v_ft,0 ,1) = '-' then '-' else '' end ;
	v_ft := case when substr(v_ft,0 ,1) = '-' then substr(v_ft, 1) else v_ft end;
	v_ft_length := length(v_key);
	
	for v_ix in (select v_ft_length) loop
		 v_i := convert(int, v_ix);
		 
	     v_c := SUBSTRING(v_ft, v_i , 1) ;
	     
	     v_i2 := case when v_i < v_ft_length then v_i else 0 end;
	     
	     v_temp := to_number(substr(v_ft,v_i2 ,1)) ^ to_number(substr(v_key,v_i2 ,1)) ;
	     
	     v_temp2 := to_number(substr(v_ft,v_i2 ,1)) - 48;
	     v_temp := case when v_temp < 10 then v_temp else v_temp2 end ;
	     
	     v_c := '' ; -- case when '.' != v_c && i < v_ft_length then convert(varchar, v_temp ) else v_c end;
	     
	     v_t := concat(v_t, v_c);
	end loop;

	return concat(v_flag, v_t);
end

convert(int, v_ix); 提示 参数类型错误，
直接用 SUBSTRING(v_ft, v_ix, 1) ; 也提示参数类型错误
是因为for循环里 v_ix不是int么？ 如何处理啊