string - listunagg 函数？

Question

oracle中有没有像listunagg函数这样的东西？例如，如果我有如下数据：

用户身份	度_fi	degree_en	degree_sv
3601464	3700	1600	2200
1020	100	0	0
3600520	100,320,400	1300、800、3000	1400、600、1500
3600882	0	100	200

我想显示这样的数据：

用户身份	度_fi	degree_en	degree_sv
3601464	3700	1600	2200
1020	100	0	0
3600520	100	1300	1400
3600882	0	100	200
3600520	3200	800	600
3600520	400	3000	1500

我试图找到一些类似的功能，listagg但找不到任何功能。

Answer 1

正如@be here now 已经在评论中指出的那样，Oracle 没有提供这样的功能。因此，作为一种快速解决方法，您可以编写类似的查询：

with t1(user_id, degree_fi, degree_en, degree_sv) as
(
  select 3601464, '3700', '1600', '2200' from dual union all
  select 1020   , '100' , '0'   , '0'    from dual union all
  select 3600520, '100,3200,400', '1300, 800, 3000', '1400, 600, 1500'  from dual union all
  select 3600882, '0',    '100',  '200'  from dual
),
Occurence(ocr) as(
  select Level as ocr
    from (select max(greatest(regexp_count(degree_fi, '[^,]+')
                             , regexp_count(degree_en, '[^,]+')
                             , regexp_count(degree_sv, '[^,]+')
                             )
                    ) mx
            from t1    
          ) 
    connect by level <= mx
)
select *
  from (
select User_id
     , regexp_substr(degree_fi, '[^,]+', 1, o.ocr) as degree_fi
     , regexp_substr(degree_en, '[^,]+', 1, o.ocr) as degree_en
     , regexp_substr(degree_sv, '[^,]+', 1, o.ocr) as degree_sv
   from t1 t
  cross join Occurence o
)
where degree_fi is not null
  or degree_en is not null 
  or degree_sv is not null

结果：

User_Id   Degree_Fi  Degree_En  Degree_Sv
------------------------------------------------------------ 
3601464   3700       1600       2200 
1020      100        0          0 
3600520   100        1300       1400 
3600882   0          100        200 
3600520   3200       800        600 
3600520   400        3000       1500 

Answer 2

OraOpenSource Utils软件包集提供了一个listunagg功能。它也很好用。

Answer 3

要取消列表，请考虑 Tom 在 Oracle 的“Ask Tom”中所说的话，请参阅https://blogs.oracle.com/oraclemagazine/on-cursors-sql-and-analytics 代码清单 3 或 4。

Tom 没有讨论的我的首选选项适用于短字符串（<34 个字符）。我使用 Oracle DBMS_UTILITY.comma_to_table 函数。例子：

SET SERVEROUTPUT ON
DECLARE
/** test data **/   
  L_LIST1   VARCHAR2(500) := '"A","B","C","Pierre - Andre","D","E","OFVampFVapos;CBryan","F","G","H","I","J"';
  l_list2   VARCHAR2(500);
  l_tablen  BINARY_INTEGER;
  l_tab     DBMS_UTILITY.uncl_array;
BEGIN
  DBMS_OUTPUT.put_line('l_list1 : ' || l_list1);

  DBMS_UTILITY.comma_to_table (
     list   => l_list1,
     tablen => l_tablen,
     tab    => l_tab);

  FOR i IN 1 .. l_tablen LOOP
    DBMS_OUTPUT.put_line(i || ' : ' || l_tab(i));
  END LOOP;

  DBMS_UTILITY.table_to_comma (
     tab    => l_tab,
     tablen => l_tablen,
     list   => l_list2);

  DBMS_OUTPUT.put_line('l_list2 : ' || l_list2);
end;