如何在Oracle 10g中基於逗號分隔值顯示逗號分隔的描述？

Question

我是Oracle技術新手。之前我因爲缺乏對這個要求的理解而發佈了同一期的2篇文章。

表1：

MSGID 
----- 
1,2,3 
2,3 
4 
null 
null 

表2：

MID MSGDESC 
---- ------- 
1  ONE 
2  TWO 
3  THREE 
4  FOUR 

預期輸出：

XCOL  DESC 
----- ----- 
1,2,3 ONE,TWO,THREE 
2,3  TWO,THREE 
4  FOUR 

我不能滿足這一要求。請給我一個解決方案。

注意：表格沒有任何唯一或主鍵值。表1有5000條記錄，表2只有80條記錄和說明。

Answer 1

create table Table1 (MSGID varchar2(100)); 

insert into Table1 values ('1,2,3'); 
insert into Table1 values ('2,3'); 
insert into Table1 values ('4'); 
insert into Table1 values (null); 
insert into Table1 values (null); 

create table Table2 (MID varchar2(100), MSGDESC varchar2(100)); 

insert into Table2 values ('1','ONE'); 
insert into Table2 values ('2','TWO'); 
insert into Table2 values ('3','THREE'); 
insert into Table2 values ('4','FOUR'); 

---

select 
    msgid as xcol, 
    "DESC", 
    col1, col2, ..., col12 
from 
    Table1 
    left join (
    select 
     msgid, 
     wm_concat(msgdesc) as "DESC" 
    from 
     (
      select 
      msgid, 
      msgdesc 
      from 
      (select distinct msgid from Table1 where ...) 
      cross join (
       select level as occ from dual connect by level <= 100) 
      ) 
      left join Table2 
       on mid = regexp_substr(msgid, '[^,]+', 1, occ) 
      where 
      occ <= regexp_count(msgid, ',') + 1 
      order by msgid, occ 
     ) 
    group by msgid 
) using (msgid)