MYSQL ORDER BY CASE問題

我有一個這樣的數據庫：MYSQL ORDER BY CASE問題

------------------------------------------------------------------- 
| id_one | id_two | timestamp_one | timestamp_two | 
------------------------------------------------------------------- 
|  27  |  35  |  9:30  |  NULL  | 
------------------------------------------------------------------- 
|  35  |  27  |  NULL  |  9:35  | 
------------------------------------------------------------------- 
|  27  |  35  |  9:34  |  NULL  | 
------------------------------------------------------------------- 
|  35  |  27  |  NULL  |  9:33  | 
-------------------------------------------------------------------

我需要把所有4行

ORDER BY 'timestamp_one' if 'id_one'=27 or 
ORDER BY 'timestamp_two' if 'id_one'=27

這是發言。我現在有：

SELECT * FROM tablename 
WHERE id_one=27 OR id_two=27 
ORDER BY 
    CASE WHEN id_one=27 THEN timestamp_one END DESC, 
    CASE WHEN id_two=27 THEN timestamp_two END DESC

這個效果很好，就是輸出這個：

------------------------------------------------------------------- 
| id_one | id_two | timestamp_one | timestamp_two | 
------------------------------------------------------------------- 
|  27  |  35  |  9:30  |  NULL  | 
------------------------------------------------------------------- 
|  27  |  35  |  9:34  |  NULL  | 
------------------------------------------------------------------- 
|  35  |  27  |  NULL  |  9:33  | 
------------------------------------------------------------------- 
|  35  |  27  |  NULL  |  9:35  | 
-------------------------------------------------------------------

但我需要兩個時間戳列訂購好像他們是一個，因此會爲了這樣的：

------------------------------------------------------------------- 
| id_one | id_two | timestamp_one | timestamp_two | 
------------------------------------------------------------------- 
|  27  |  35  |  9:30  |  NULL  | 
------------------------------------------------------------------- 
|  35  |  27  |  NULL  |  9:33  | 
------------------------------------------------------------------- 
|  27  |  35  |  9:34  |  NULL  | 
------------------------------------------------------------------- 
|  35  |  27  |  NULL  |  9:35  | 
-------------------------------------------------------------------

我希望這是有道理的。基本上，我想有兩個特定於WHERE條件的ORDER BY列。然後，一旦爲該行選擇了正確的ORDER BY列，它就會將整個時間戳的ROWS排序。

來源

2010-12-03 ATLChris

您是不是要找「ORDER BY如果 'id_two'= 27 'timestamp_two'」？ – buru 2010-12-03 15:09:23

如果一個時間戳或另一個時間戳總是`NULL`，那麼執行`ORDER BY IFNULL（timestamp_one，timestamp_two）`可能會更清晰。 – dkarp 2015-04-28 17:11:42

SELECT id_one, id_two, timestamp_one, timestamp_two  
FROM tablename 
WHERE id_one = 27 
    OR id_two = 27 
ORDER BY 
    CASE 
     WHEN id_one=27 THEN timestamp_one 
     WHEN id_two=27 THEN timestamp_two 
    END DESC

來源

2010-12-03 15:10:10 RedFilter

謝謝你，工作完美！ – ATLChris 2010-12-03 15:19:33

SELECT 
    id_one, 
    id_two, 
    (CASE 
     WHEN id_one=27 THEN timestamp_one 
     WHEN id_two=27 THEN timestamp_two  
    END) as timestamp 
FROM tablename 
ORDER BY timestamp DESC

來源

2010-12-03 15:17:07 buru

SELECT * FROM tablename 
WHERE id_one=27 OR id_two=27 
ORDER BY id ASC, timestamp_one DESC

來源

2015-04-28 16:54:28 Esdras

MYSQL ORDER BY CASE問題

回答

相關問題