我想創建一個Y/N標誌。如果其中一個帳戶以M結尾，則標記爲否否Y如果全部以D結尾

Question

SELECT CASE SUBSTR（ACCOUNT，6,1）='M'THEN'N'ELSE'Y'END as POSTING_FLAG FROM ALL_QUEUES

所需的輸出：

帳戶標誌

12345Dñ

12345Dñ

12345Dñ

12345Mň

22222DŸ

22222DŸ

22222DŸ

22222DŸ

Answer 1

您可以使用分析功能;這種使用CTE提供基礎數據與剛剛在帳戶：

with all_queues (account) as (
    select '12345D' from dual 
    union all select '12345D' from dual 
    union all select '12345D' from dual 
    union all select '12345M' from dual 
    union all select '22222D' from dual 
    union all select '22222D' from dual 
    union all select '22222D' from dual 
    union all select '22222D' from dual 
) 
select account, 
    case max(substr(account, -1)) 
     over (partition by substr(account, 1, length(account) - 1)) 
    when 'M' then 'N' else 'Y' end as posting_flag 
from all_queues; 

ACCOUNT POSTING_FLAG 
------- ------------ 
12345D N 
12345D N 
12345D N 
12345M N 
22222D Y 
22222D Y 
22222D Y 
22222D Y 

8 rows selected. 

如果帳戶確實總是七個字符，那麼你可以簡化分區子。