mysql中的制表符替换

-- 问题重现
set @v_t='    ';
select hex(@v_t)
-- 原因：    
-- ASCII格式的hex进展ox09对应char为(ht)制表tab，喔原来是有很多的制表符吧.

-- 数据库中去掉的办法
set @v_t='    ';
select f_sql_clearspace('    ');

-- java中的解决方法:
replace("\\t","")

CREATE DEFINER=`root`@`%` FUNCTION `f_sql_clearspace`(v_sql varchar()) RETURNS varchar() CHARSET utf8
begin
  declare v_tmps varchar() default '';
  declare v_last varchar() default '';
  declare v_curr varchar() default '';
  declare v_num int default ;
  declare v_max int default ;

  set v_max = length(v_sql);
  while v_num <> v_max do
    set v_num = v_num + ;
    set v_curr = substr(v_sql, v_num, );

    if (v_curr = char() or v_curr = char()) then
      set v_curr = char();
    end if;

    if (v_curr <> char() and (v_last is null or v_last <> char())) then
      set v_tmps = concat(v_tmps, v_curr);
      set v_last = v_curr;
    elseif (v_last <> char() and v_curr = char()) then
      set v_tmps = concat(v_tmps, v_curr);
      set v_last = v_curr;
    elseif (v_last = char() and v_curr <> char()) then
      set v_tmps = concat(v_tmps, v_curr);
      set v_last = v_curr;
    end if;
  end while;

  return v_tmps;
end