Question

我有一个看起来像这样的表：

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

我需要找出连续三个月的价值是否有所增加。

如何让SQL检查每个值是否增加了？如果有人能给我任何解决这个问题的指示，我将不胜感激！

由于

Answer 1

@n代表您要检查的连续值的数量少于2（在您的情况下为2）：

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;

递归SQL，最后三个值增加了吗？

1 个答案: