小编car*_*arl的帖子

问题存在于MySQL的最新版本中,所以我甚至怀疑这可能是一个错误.

这是两个表:

t1(id int), values (10),(2)
t2(id int), values (0),(null),(1)

执行:

select id from t1 where id > all (select id from t2);

返回结果集:

+------+
| id   |
+------+
|   10 |
|    2 |
+------+

根据我的知识和页面http://dev.mysql.com/doc/refman/5.5/en/all-subqueries.html

该语句应返回空结果!因为"where"中的每个判断都会导致null,如下所示:

select id > all (select id from t2)  as c1 from t1;

收益:

+------+
| c1   |
+------+
| NULL |
| NULL |
+------+

实际上select id from t1 where null;什么也没有回报

最后,我尝试了这个:

explain extended select id from t1 where …

我试图建立hMailServer在"Windows Server 2008企业版Service Pack 1" .I've设置hMailServer,阿帕奇,PHP和Webmail界面"AfterLogic的webMail" successfully.And一切工作well.But我被困在同时问题我试图安装" PHPWebAdmin ".错误信息如下:

Fatal error: Class 'COM' not found in E:\Server\wwwroot\PHPWebAdmin\initialize.php on line 13

访问"http://192.168.2.66:8088/PHPWebadmin/"时会出现此信息.

我已经配置PHP配置文件php.ini选项如下:

[PHP]
register_globals = Off
display_errors = Off

doc_root = "E:/Server/wwwroot"
extension_dir = "E:/Server/php5_4_5/ext"

[Session]
session.save_path = "E:/Server/php5_4_5/tmp"

[COM]
com.allow_dcom = true

我也完成了这些事情,因为hMailServer手册建议:

DCOM permissions
Overview
By default, IIS6 is not allowed to connect to hMailServer because of the Distributed COM permissions that Windows uses. Also, Apache run as a user account with restricted permissions …