Oracle SQL从表中获取唯一符号

我有一张表，上面有smth的说明。例如：

My_Table id description ================ 1 ABC 2 ABB 3 OPAC 4 APEЧ 我需要从所有描述列中获取所有唯一的符号。 结果应该是这样的：

symbol ================ A B C O P E Ч 它应该适用于所有语言，所以，正如我所看到的，正则表达式帮不上忙。

---

请帮帮我。谢谢。

创建一个数字表，并用本例中所需的所有相关ID填充它1..maxlength of string

SELECT DISTINCT
  locate(your_table.description, numbers.id)   AS symbol
FROM
  your_table
INNER JOIN
  numbers
    ON  numbers.id >= 1
    AND numbers.id <= CHAR_LENGTH(your_table.description)

或

---

你对所有语言都意味着什么？所有dbms？最大字符串长度是多少？结果的顺序重要吗？不，只有Oracle SQL。我的意思是，在description列中可以是任何语言的文本：英语、法语、俄语等。输入字符串可以是任何大小，输出字符串应该包含一个符号。例如，一个符号对应一条记录。顺序无关紧要。输入字符串不能有任何大小。表格本身将定义字段的最大大小。非常感谢，这正是我所需要的。纯代码答案对读者的教育作用不大。请编辑您的答案，包括一些解释。您的答案在审核队列中，因为它已被标记为低质量。

with    cte (c,description_suffix) as
        (
            select  substr(description,1,1)
                   ,substr(description,2)
            from    mytable
            where   description is not null

            union all

            select  substr(description_suffix,1,1)
                   ,substr(description_suffix,2)
            from    cte
            where   description_suffix is not null
        )
select    c
         ,count(*) as cnt
from      cte
group by  c
order by  c 

with    cte(n) as
        (
            select      level 
            from        dual 
            connect by  level <= (select max(length(description)) from mytable)
        )
select  substr(t.description,c.n,1) as c
       ,count(*)                    as cnt
from            mytable t
        join    cte c
        on      c.n <= length(description)
group by substr(t.description,c.n,1)
order by c

+---+-----+
| C | CNT |
+---+-----+
| A |   4 |
| B |   3 |
| C |   2 |
| E |   1 |
| O |   1 |
| P |   2 |
| Ч |   1 |
+---+-----+

SELECT DISTINCT(SUBSTR(ll,LEVEL,1)) OP --Here DISTINCT(SUBSTR(ll,LEVEL,1)) is used to get all distinct character/numeric in vertical as per requirment
FROM
( 
    SELECT LISTAGG(DES,'') 
    WITHIN GROUP (ORDER BY ID) ll 
    FROM My_Table  --Here listagg is used to convert all values under description(des) column into a single value and there is no space in between
)
CONNECT BY LEVEL <= LENGTH(ll);