MySQL的NOW（）列不正确的时间值 - 错误代码1292

Question

做时使用简单的数学NOW（）...

mysql> 
select cdrstatuschangets from cdrs where (cdrstatuschangets < now() - 10); 
    +---------------------+ 
    | cdrstatuschangets | 
    +---------------------+ 
    | 2009-09-25 13:55:50 | 
    +---------------------+ 
    1 row in set (0.00 sec) 

    show warnings; 
    Empty set (0.00 sec) 

经常的工作，但有时，...

mysql> 
select cdrstatuschangets from cdrs where (cdrstatuschangets < now() - 50); 
    +---------------------+ 
    | cdrstatuschangets | 
    +---------------------+ 
    | 2009-09-25 13:55:50 | 
    +---------------------+ 
    1 row in set, 1 warning (0.00 sec) 


show warnings; 
+---------+------+-----------------------------------------------------------------------+ 
| Level | Code | Message |                     | 
+---------+------+-----------------------------------------------------------------------+ 
| Warning | 1292 | Incorrect datetime value: '20090925211564.000000' for column 'cdrStatusChangeTS' at row 1 | 
+---------+------+-----------------------------------------------------------------------+ 
1 row in set (0.00 sec) 

，有时尽管预期会出现选择结果。

Answer 1

有一个阴险的问题做用简单的数学NOW（）...秒和分钟等减法是基于一分钟打100秒，并以每小时100分钟......

有时似乎工作和其他时间没有。阴险。

mysql> select now(); select now() -10; 
+---------------------+ 
| now()    | 
+---------------------+ 
| 2009-09-25 21:07:20 | 
+---------------------+ 
1 row in set (0.00 sec) 

+-----------------------+ 
| now() -10    | 
+-----------------------+ 
| 20090925210710.000000 | 
+-----------------------+ 
1 row in set (0.00 sec) 

一切都很好，但是......

mysql> select now(); select now() -10; 
+---------------------+ 
| now()    | 
+---------------------+ 
| 2009-09-25 21:08:02 | 
+---------------------+ 
1 row in set (0.00 sec) 

+-----------------------+ 
| now() -10    | 
+-----------------------+ 
| 20090925210792.000000 | 
+-----------------------+ 
1 row in set (0.00 sec) 

显示时间戳（看起来像一个时间戳）92秒。

原来我需要做更多的东西一样

select cdrstatuschangets from cdrs where (cdrstatuschangets < now() - INTERVAL 50 SECOND); 

但它的问题是“受伤”的间歇性。

Answer 2

我建议使用DateAdd来代替可靠性和可读性。