求一条sql话语。 _PHP

求一条sql语句。。
想了半天，也没个头绪不知道该怎么写。
我要查询DISCUZ X2.0的三个表，分别是pre_forum_thread，pre_forum_attachment索引表,pre_forum_attachment_n的子表

SQL code


CREATE TABLE IF NOT EXISTS `pre_forum_thread` (
  `tid` mediumint(8) unsigned NOT NULL AUTO_INCREMENT,
  `fid` mediumint(8) unsigned NOT NULL DEFAULT '0',
  `posttableid` smallint(6) unsigned NOT NULL DEFAULT '0',
  `typeid` smallint(6) unsigned NOT NULL DEFAULT '0',
  `sortid` smallint(6) unsigned NOT NULL DEFAULT '0',
  `readperm` tinyint(3) unsigned NOT NULL DEFAULT '0',
  `price` smallint(6) NOT NULL DEFAULT '0',
  `author` char(15) NOT NULL DEFAULT '',
  `authorid` mediumint(8) unsigned NOT NULL DEFAULT '0',
  `subject` char(80) NOT NULL DEFAULT '',
  `dateline` int(10) unsigned NOT NULL DEFAULT '0',
  `lastpost` int(10) unsigned NOT NULL DEFAULT '0',
  `lastposter` char(15) NOT NULL DEFAULT '',
  `views` int(10) unsigned NOT NULL DEFAULT '0',
  `replies` mediumint(8) unsigned NOT NULL DEFAULT '0',
  `displayorder` tinyint(1) NOT NULL DEFAULT '0',
  `highlight` tinyint(1) NOT NULL DEFAULT '0',
  `digest` tinyint(1) NOT NULL DEFAULT '0',
  `rate` tinyint(1) NOT NULL DEFAULT '0',
  `special` tinyint(1) NOT NULL DEFAULT '0',
  `attachment` tinyint(1) NOT NULL DEFAULT '0',
  `moderated` tinyint(1) NOT NULL DEFAULT '0',
  `closed` mediumint(8) unsigned NOT NULL DEFAULT '0',
  `stickreply` tinyint(1) unsigned NOT NULL DEFAULT '0',
  `recommends` smallint(6) NOT NULL DEFAULT '0',
  `recommend_add` smallint(6) NOT NULL DEFAULT '0',
  `recommend_sub` smallint(6) NOT NULL DEFAULT '0',
  `heats` int(10) unsigned NOT NULL DEFAULT '0',
  `status` smallint(6) unsigned NOT NULL DEFAULT '0',
  `isgroup` tinyint(1) NOT NULL DEFAULT '0',
  `favtimes` mediumint(8) NOT NULL DEFAULT '0',
  `sharetimes` mediumint(8) NOT NULL DEFAULT '0',
  `stamp` tinyint(3) NOT NULL DEFAULT '-1',
  `icon` tinyint(3) NOT NULL DEFAULT '-1',
  `pushedaid` mediumint(8) NOT NULL DEFAULT '0',
  `cover` smallint(6) NOT NULL DEFAULT '0',
  `replycredit` smallint(6) NOT NULL DEFAULT '0',
  PRIMARY KEY (`tid`),
  KEY `digest` (`digest`),
  KEY `sortid` (`sortid`),
  KEY `displayorder` (`fid`,`displayorder`,`lastpost`),
  KEY `typeid` (`fid`,`typeid`,`displayorder`,`lastpost`),
  KEY `recommends` (`recommends`),
  KEY `heats` (`heats`),
  KEY `authorid` (`authorid`),
  KEY `isgroup` (`isgroup`,`lastpost`),
  KEY `special` (`special`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8 AUTO_INCREMENT=380 ;

pre_forum_attachment结构如下：

SQL code

CREATE TABLE IF NOT EXISTS `pre_forum_attachment` (
  `aid` mediumint(8) unsigned NOT NULL AUTO_INCREMENT,
  `tid` mediumint(8) unsigned NOT NULL DEFAULT '0',
  `pid` int(10) unsigned NOT NULL DEFAULT '0',
  `uid` mediumint(8) unsigned NOT NULL DEFAULT '0',
  `tableid` tinyint(1) unsigned NOT NULL DEFAULT '0',
  `downloads` mediumint(8) NOT NULL DEFAULT '0',
  PRIMARY KEY (`aid`),
  KEY `tid` (`tid`),
  KEY `pid` (`pid`),
  KEY `uid` (`uid`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8 AUTO_INCREMENT=110 ;

pre_forum_attachment_n子表结构如下

SQL code

CREATE TABLE IF NOT EXISTS `pre_forum_attachment_0` (
  `aid` mediumint(8) unsigned NOT NULL,
  `tid` mediumint(8) unsigned NOT NULL DEFAULT '0',
  `pid` int(10) unsigned NOT NULL DEFAULT '0',
  `uid` mediumint(8) unsigned NOT NULL DEFAULT '0',
  `dateline` int(10) unsigned NOT NULL DEFAULT '0',
  `filename` varchar(255) NOT NULL DEFAULT '',
  `filesize` int(10) unsigned NOT NULL DEFAULT '0',
  `attachment` varchar(255) NOT NULL DEFAULT '',
  `remote` tinyint(1) unsigned NOT NULL DEFAULT '0',
  `description` varchar(255) NOT NULL,
  `readperm` tinyint(3) unsigned NOT NULL DEFAULT '0',
  `price` smallint(6) unsigned NOT NULL DEFAULT '0',
  `isimage` tinyint(1) NOT NULL DEFAULT '0',
  `width` smallint(6) unsigned NOT NULL DEFAULT '0',
  `thumb` tinyint(1) unsigned NOT NULL DEFAULT '0',
  `picid` mediumint(8) NOT NULL DEFAULT '0',
  PRIMARY KEY (`aid`),
  KEY `tid` (`tid`),
  KEY `pid` (`pid`),
  KEY `uid` (`uid`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;