聯盟合併不同列

Question

我有兩個表：

Table1：

DATAID| NAME | FACTOR 

1 | Ann | 1 
2 | Kate | 1 
3 | Piter | 1 

Table2：

DATAID| NAME | FACTOR 

1 | John | 2 
6 | Arse | 2 
3 | Garry | 2 

我想UNION這些表，並得到這樣的結果：

DATAID| NAME | FACTOR 

1 | Ann  | 1,2 
2 | Kate | 1 
3 | Piter | 1,2 
6 | Arse | 2 

因此，當有2行與同一數據ID，我想獲得從表1「姓名」列和某種聚合因子，例如「1,2」或3

Answer 1

一種方法是使用listagg()：

select dataid, name, 
     listagg(factor, ',') within group (order by factor) as factors 
from ((select dataid, name, factor from table1 t1 
    ) union all 
     (select dataid, name, factor from table2 t2 
    ) 
    ) t 
group by dataid, name; 

注：我注意到名稱是而不是對於給定的id是相同的。您可以使用聚合功能選擇一個。

或者，如果你只有一個行中的每個表，你可以使用一個full outer join：

select coalesce(t1.dataid, t2.dataid) as dataid, 
     coalesce(t1.name, t2.name) as name, 
     trim(leading ',' from coalesce(',' || t1.factor, ',') || coalesce(',' || t2.factor, '') as factors 
from t1 full outer join 
    t2 
    on t1.dataid = t2.dataid; 

Answer 2

這樣的事情應該工作。在你的實際情況中，你將不需要前兩個CTE（我爲增加測試添加的WITH子句中的子查詢）。

with 
    table1 (dataid, name, factor) as (
     select 1, 'Ann' , 1 from dual union all 
     select 2, 'Kate' , 1 from dual union all 
     select 3, 'Piter', 1 from dual 
    ), 
    table2 (dataid, name, factor) as (
     select 1, 'John' , 2 from dual union all 
     select 6, 'Arse' , 2 from dual union all 
     select 3, 'Garry', 2 from dual 
    ), 
    u (dataid, name, factor, source) as (
     select dataid, name, factor, 1 from table1 
     union all 
     select dataid, name, factor, 2 from table2 
    ), 
    z (dataid, name, factor) as (
     select dataid, first_value(name) over (partition by dataid order by source), 
       factor 
     from u 
    ) 
select dataid, name, 
     listagg(factor, ',') within group (order by factor) as factor 
from z 
group by dataid, name 
order by dataid 
; 

輸出：

DATAID NAME FACTOR 
------- ----- --------- 
     1 Ann 1,2 
     2 Kate 1 
     3 Piter 1,2 
     6 Arse 2 

4 rows selected.