mysql - 使用 subtime() 的查询意外地没有返回任何行

Question

我正在使用以下查询:

 SELECT message,timestamp 
 FROM botlogs.tbllogs
 WHERE message like '%Failed to grab car amount 
       or 0 website%' and timestamp > Subtime('2011-08-01 13:20','0:60')

虽然我有 8/1/2011 1:21:53pm 的行，但上述查询不返回任何行。这是为什么？

如果我运行

select timestamp,message 
from botlogs.tbllogs 
where message like Failed to grab car amount 
       or 0 website%' and timestamp < '2011-08-01 13:20' - INTERVAL 180 SECOND

它返回 7/31/2011 9:27:24 pm 的错误。

Answer 1

因为:

mysql> SELECT Subtime('2011-08-01 13:20','0:60');
+------------------------------------+
| Subtime('2011-08-01 13:20','0:60') |
+------------------------------------+
| NULL                               |
+------------------------------------+
1 row in set, 1 warning (0.04 sec)

试试这个

mysql> SELECT Subtime('2011-08-01 13:20','00:01:00');
+----------------------------------------+
| Subtime('2011-08-01 13:20','00:01:00') |
+----------------------------------------+
| 2011-08-01 13:19:00                    |
+----------------------------------------+
1 row in set (0.00 sec)

或者

mysql> SELECT '2011-08-01 13:20' - INTERVAL 60 SECOND;
+-----------------------------------------+
| '2011-08-01 13:20' - INTERVAL 60 SECOND |
+-----------------------------------------+
| 2011-08-01 13:19:00                     |
+-----------------------------------------+
1 row in set (0.01 sec)