MySQL的：有两个不同的列查询不同的列日期

Question

，我有以下结果从查询

SELECT DISTINCT user_id, 
       IF(ra.status = 1, created_datetime, 'No record') AS ACTIVATED, 
       IF(ra.status = 0, created_datetime, 'No record') AS DE_ACTIVATED 
FROM accounts ra 
WHERE user_id IN (12345678); 

+----------+---------------------+---------------------+ 
| user_id | ACTIVATED   | DE_ACTIVATED  | 
+----------+---------------------+---------------------+ 
| 12345678 | No record   | 2013-04-28 02:32:36 | 
| 12345678 | 2013-03-28 02:32:36 | No record   | 
+----------+---------------------+---------------------+ 

我想只有1行的记录，结合激活和去激活。基本上，这样做。

+----------+---------------------+---------------------+ 
| user_id | ACTIVATED   | DE_ACTIVATED  | 
+----------+---------------------+---------------------+ 
| 12345678 | 2013-03-28 02:32:36 | 2013-04-28 02:32:36 | 
+----------+---------------------+---------------------+ 

任何帮助是非常感谢，因为我建立我的查询忍者技能。

问候

Answer 1

以这两个条件的MAX，但要“假”条件评估为null。然后把它包在COALESCE所以如果calcualted MAX为null，它会与no record替代：

SELECT user_id, 
    COALESCE(MAX(IF(ra.status = 1, created_datetime, null)), 'No record') AS Activated, 
    COALESCE(MAX(IF(ra.status = 0, created_datetime, null)), 'No record') AS Deactivated 
FROM accounts ra 
WHERE user_id IN (12345678) 

如果你会查询一个以上的用户，这添加到末尾：

GROUP BY user_id