Oracle存储过程中去掉重复字符串的函数

    以下函数是本人在编写Oracle数据库存储过程时写的函数,觉得该函数通用性较强,因此发表出来供需要的人参考.

这个函数的功能主要是用于去除给定字符串中重复的字符串.在使用中需要指定字符串的分隔符.示例:
str := MyReplace('13,14,13,444', ',');
输出:
13,14,444

create or replace function MyReplace(oldStr varchar2, sign varchar2) return varchar2 is
str varchar2(1000);
currentIndex number;
startIndex number;
endIndex number;

type str_type is table of varchar2(30)
       index by binary_integer;
arr str_type;

Result varchar2(1000);
begin
if oldStr is null then
    return ('');
end if;

str := oldStr;

currentIndex := 0;
startIndex := 0;
loop
    currentIndex := currentIndex + 1;
    endIndex := instr(str, sign, 1, currentIndex);
    if (endIndex <= 0) then
      exit;
end if;

arr(currentIndex) := trim(substr(str, startIndex + 1, endIndex - startIndex - 1));
startIndex := endIndex;
end loop;

--取最后一个字符串
arr(currentIndex) := substr(str, startIndex + 1, length(str));

--去掉重复出现的字符串
for i in 1.. currentIndex - 1 loop
for j in i + 1..currentIndex loop
    if arr(i) = arr(j) then
      arr(j) := '';
    end if;
end loop;
end loop;

str := '';
for i in 1..currentIndex loop
if arr(i) is not null then
    str := str sign arr(i);

    --数组置空
    arr(i) := '';
end if;
end loop;

--去掉前面的标识符
Result := substr(str, 2, length(str));
return(Result);
end MyReplace;