獲取多個數據到一個colomn Oracle查詢

Question

我有3個表格：table_A，table_B和table_C。 Table_A有一個主鍵，並由來自table_B的外鍵引用。 Table_C有一個由table_B的外鍵引用的主鍵。設計是這樣的：

 
Table_A: 
ID_A 
TextData 

 
Table_B: 
ID_B 
ID_A 
ID_C 

 
Table C: 
ID_C 
TextData 

我想3臺這樣的之間加入：

 
select A.ID_A, A.TextData as DataA, 
(
    select C.TextData 
    from Table_B B, Table_C C 
    where B.ID_C = C.ID_C and B.ID_A = C.ID_A 
) as Data_C 
from Table_A; 

我知道，如果我嘗試編譯它，它應該是一個錯誤帶有如下錯誤：返回多個元素。

但我的客戶想讓我把表C中的所有數據合併成一行，我只知道使用concatep來處理每個數據。但我不知道該怎麼做。我從來沒有嘗試在oracle上創建函數或包。你能幫我解決我的問題嗎？

結果應該是這樣的：

 
ID_A | DataA  | Data_C 
1   texta  text1, text2, text8 
2   textb  text2, text3, text9 
3   textc  text1, text8, text9 

Answer 1

XMLAGG或類似的是你所需要的。喜歡的東西（未測試，但應該給你一個提示）：

select A.ID_A, A.TextData as DataA, 
(
    select XMLELEMENT("Thedata",XMLAGG("textdata",C.TextData)) as td 
    from Table_B B, Table_C C 
    where B.ID_C = C.ID_C and B.ID_A = C.ID_A 
) as Data_C 
from Table_A; 

使用替換/翻譯/ REGEXP_REPLACE等，如果需要剝離出XML標記。

有關例如http://www.dba-oracle.com/t_converting_rows_columns.htm。

Answer 2

也許你應該寫你的聚合。 Funcrion來連接你的字符串user defined aggregates

或者使用未公開的wm_concat。因此在12c中棄用了函數。

Answer 3

如果你在Oracle 11g或更高版本，可以使用LISTAGG：

with table_a as (select 1 id_a, 'texta' textdata from dual union all 
       select 2 id_a, 'textb' textdata from dual union all 
       select 3 id_a, 'textc' textdata from dual), 
    table_b as (select 1 id_b, 1 id_a, 1 id_c from dual union all 
       select 2 id_b, 1 id_a, 2 id_c from dual union all 
       select 3 id_b, 1 id_a, 4 id_c from dual union all 
       select 4 id_b, 2 id_a, 2 id_c from dual union all 
       select 5 id_b, 2 id_a, 3 id_c from dual union all 
       select 6 id_b, 2 id_a, 5 id_c from dual union all 
       select 7 id_b, 3 id_a, 1 id_c from dual union all 
       select 8 id_b, 3 id_a, 4 id_c from dual union all 
       select 9 id_b, 3 id_a, 5 id_c from dual), 
    table_c as (select 1 id_c, 'text1' textdata from dual union all 
       select 2 id_c, 'text2' textdata from dual union all 
       select 3 id_c, 'text3' textdata from dual union all 
       select 4 id_c, 'text8' textdata from dual union all 
       select 5 id_c, 'text9' textdata from dual) 
-- end of mimicking your tables; see sql below. 
select a.id_a, 
     a.textdata, 
     listagg(c.textdata, ', ') within group (order by c.id_c) data_c 
from table_a a 
     inner join table_b b on (a.id_a = b.id_a) 
     inner join table_c c on (b.id_c = c.id_c) 
group by a.id_a, a.textdata; 

     ID_A TEXTDATA DATA_C    
---------- -------- -------------------- 
     1 texta text1, text2, text8 
     2 textb text2, text3, text9 
     3 textc text1, text8, text9 

Answer 4

你可以用這個嘗試：

SETUP

create table table_A(ID_A number, TextData varchar2(100)) 
/
create table Table_B(ID_B number, ID_A number, ID_C number) 
/
create table Table_C(ID_C number, TextData varchar2(100)) 
/
insert into table_A values (1, 'texta'); 
insert into table_A values (2, 'textb'); 
insert into table_A values (3, 'textc'); 
-- 
insert into table_C values (1, 'text1'); 
insert into table_C values (2, 'text2'); 
insert into table_C values (3, 'text3'); 
insert into table_C values (8, 'text8'); 
insert into table_C values (9, 'text9'); 
-- 
insert into table_b values (11, 1, 1); 
insert into table_b values (12, 1, 2); 
insert into table_b values (18, 1, 8); 
insert into table_b values (22, 2, 2); 
insert into table_b values (23, 2, 3); 
insert into table_b values (29, 2, 9); 
insert into table_b values (31, 3, 1); 
insert into table_b values (38, 3, 8); 
insert into table_b values (39, 3, 8); 

QUERY：

select id_a, a.textData as DataA, listagg(c.textData, ', ') within group (order by c.textData) as Data_c 
from table_A a 
    inner join table_B b 
    using(id_A) 
    inner join table_c c 
    using(id_c) 
group by id_a, a.textData