MySQL日期时间查询的奇怪问题

Question

这些结果如何有意义？我不明白.
不应该例如最后一个查询返回一个空集,因为没有日期的线程> 2010？为什么从2003年返回结果？

mysql> SELECT * 
       FROM thread 
       WHERE newsgroup_id = '64654' 
       AND 'thread_date' < '2010-09-10 21:43:05' 
       LIMIT 1;

空集(0.00秒)

mysql> SELECT * 
       FROM thread 
       WHERE newsgroup_id = '64654' 
       AND 'thread_date' < '2000-09-10 21:43:05' 
       LIMIT 1;

空集(0.00秒)

mysql> SELECT * 
       FROM thread 
       WHERE newsgroup_id = '64654' 
       AND 'thread_date' > '2000-09-10 21:43:05' 
       LIMIT 1;
+--------------+-----------+-----------+----------+---------------------+---------------------+---------------------------------+-------------------------+
| newsgroup_id | thread_id | postcount | hash     | thread_date         | thread_date_last        | thread_title                    | title_has_valid_charset |
+--------------+-----------+-----------+----------+---------------------+---------------------+---------------------------------+-------------------------+
|        64654 |         1 |         0 | O2gvcPRl | 2003-06-06 22:51:24 | 0000-00-00 00:00:00 | Vendo fotodigit  2.1  megapixel |                       0 |
+--------------+-----------+-----------+----------+---------------------+---------------------+---------------------------------+-------------------------+

1排(0.00秒)

mysql> SELECT * 
       FROM thread 
       WHERE newsgroup_id = '64654' 
       AND 'thread_date' > '2010-09-10 21:43:05' 
       LIMIT 1;
+--------------+-----------+-----------+----------+---------------------+---------------------+---------------------------------+-------------------------+
| newsgroup_id | thread_id | postcount | hash     | thread_date         | thread_date_last    | thread_title                    | title_has_valid_charset |
+--------------+-----------+-----------+----------+---------------------+---------------------+---------------------------------+-------------------------+
|        64654 |         1 |         0 | O2gvcPRl | 2003-06-06 22:51:24 | 0000-00-00 00:00:00 | Vendo fotodigit  2.1  megapixel |                       0 |
+--------------+-----------+-----------+----------+---------------------+---------------------+---------------------------------+-------------------------+

1排(0.00秒)

Answer 1

您使用了错误的报价类型.MySQL认为你正在比较字符串"thread_date".这是应该如何:

`thread_date` > '2010-09-10 21:43:05'

这样MySQL知道你的意思是字段thread_date并将它与表达式右侧的日期进行比较.