遞歸SQL，最近三個值增加了嗎？

Question

我有一個表，看起來像這樣：

---------------------- 
| DateTime | Value | 
---------------------- 
| 2010-01-01 | 26 | 
| 2010-02-01 | 24 |  
| 2010-03-01 | 23 | 
| 2010-04-01 | 28 | 
| 2010-05-01 | 30 | 

我需要找到如果最近連續3個月的價值也隨之增加。

我怎樣才能讓SQL檢查每個值是否增加？ 如果任何人都可以給我任何解決這個問題的指針，將不勝感激！

感謝

Answer 1

隨着@n站在一個小於要檢查連續值（2，在您的案件）數量：

SELECT MIN(increase) AS increasing 
    FROM (SELECT t1.`Value` > t2.`Value` AS increase 
      FROM tbl AS t1 
      JOIN tbl AS t2 
       ON t1.`DateTime` = t2.`DateTime` + INTERVAL 1 month 
      WHERE t1.DateTime < '2010-06-01' 
      ORDER BY t1.`DateTime` DESC 
      LIMIT @n) AS tmp; 

或：

SELECT MIN(t1.`Value` > t2.`Value`) AS increasing 
    FROM tbl AS t1 
    JOIN tbl AS t2 
     ON t1.`DateTime` = t2.`DateTime` + INTERVAL 1 month 
    WHERE t1.`DateTime` > NOW() - INTERVAL 3 month;