listagg Oracle SQL Query，加入同一張表

Question

對於每隻狗，我想找到除狗以外的其他動物的匹配名稱，並將它們添加到逗號分隔列表中。表圖像和下面的查詢期望的結果：

一個表，這種結構存在：

而且我想創建結果，如查詢：

Answer 1

可以使用self-join，然後是listagg。

select tdog.animal,tdog.name 
,listagg(tother.animal||'-'||tother.name||'-'||tother.id) within group(order by tother.id) 
from tablename tdog 
join tablename tother on tdog.name=tother.name and tdog.animal='dog' and tother.animal <> 'dog' 
group by tdog.animal,tdog.name 

Answer 2

有了一些技巧，你不需要self join：

select 'dog' as animal, name, 
     listagg(case when animal <> 'dog' then animal || '-' || name || '-' || id 
       end), ',') within group (order by id) as animals 
from t 
group by name 
having sum(case when animal = 'dog' then 1 else 0 end) > 0