如何通過Oracle中兩個查詢的聯合結果進行排序？

Question

我有以下Oracle SQL工作正常，但第二個查詢的結果返回第一行而不是第二個。

如何維護輸出中的序列，以便第一個查詢結果顯示在第一行，第二個顯示在第二行等等。

的Oracle SQL

select 
    sum(a.transaction_amount) as transaction_amount, 
    'Last 30 Days Debit Volume (Current Year)' as sales_volume 
from 
    payment_transaction a, 
    payment_settlement b 
where 
    a.transaction_status = 'S' 
    and b.settlement_type = 'D' 
    and trunc(b.transaction_date) > sysdate - 30 
    and a.payment_transaction_id = b.payment_transaction_id 

union 

select 
    sum(a.transaction_amount) as transaction_amount, 
    'Last 30 Days Credit Volume (Current Year)' as sales_volume 
from 
    payment_transaction a, 
    payment_settlement b 
where 
    a.transaction_status = 'S' 
    and b.settlement_type = 'C' 
    and trunc(b.transaction_date) > sysdate - 30 
    and a.payment_transaction_id = b.payment_transaction_id 

電流輸出

TRANSACTION_AMOUNT  SALES_VOLUME 
6272      Last 30 Days Credit Volume (Current Year) 
10719     Last 30 Days Debit Volume (Current Year) 

期望輸出

TRANSACTION_AMOUNT  SALES_VOLUME 
10719     Last 30 Days Debit Volume (Current Year) 
6272      Last 30 Days Credit Volume (Current Year) 

Answer 1

只需添加一個dummy column to sort

SELECT <yourfields> 
FROM (
     SELECT 1 as dummy, <yourfields> 
     FROM Query1 
     UNION 
     SELECT 2 as dummy, <yourfields> 
     FROM Query2 
    ) T 
ORDER BY dummy