您可以通过两种方式编写查询
1. 使用相关查询
2. 使用会话变量
第一个正是ethrbunny指出的
mysql> SELECT t1.id,
t1.store_id,
timestampdiff(second,IFNULL( (SELECT MAX(t2.timestamp)
FROM print t2
WHERE t2.store_id=2
AND t2.timestamp< t1.timestamp)
,t1.timestamp),t1.timestamp) myTimeDiffSeconds
FROM print t1
WHERE t1.store_id=2 ORDER BY t1.timestamp;
+------+----------+-------------------+
| id | store_id | myTimeDiffSeconds |
+------+----------+-------------------+
| 2 | 2 | 0 |
| 4 | 2 | 11 |
| 6 | 2 | 3 |
+------+----------+-------------------+
3 rows in set (0.00 sec)
另一种方法是使用会话变量来保存以前的时间,但是在这种情况下,我们需要第一次获取最小时间戳
mysql> select min(p.timestamp) into @prev_time from print p where p.store_id=2;
Query OK, 1 row affected (0.00 sec)
mysql> select id,
store_id,
timestampdiff(second,@prev_time,timestamp) myTimeDiffSeconds,
@prev_time:=timestamp
from print
where store_id=2 order by timestamp;
+------+----------+-------------------+---------------------+
| id | store_id | myTimeDiffSeconds | @prev_time:=t |
+------+----------+-------------------+---------------------+
| 2 | 2 | 0 | 2013-03-01 00:00:01 |
| 4 | 2 | 11 | 2013-03-01 00:00:12 |
| 6 | 2 | 3 | 2013-03-01 00:00:15 |
+------+----------+-------------------+---------------------+
3 rows in set (0.00 sec)
(timestamp,store_id) 上的索引将使查询执行得更好。