php 同时查询多个表
$Uid=$_SESSION["Uid"]; 获得$Uid
$result="SELECT * FROM reply where Uid='$Uid' group by Tid order by Rdate DESC limit $offset,$Page_size";
$queryr=$obj->exec($result);
while ($row=mysql_fetch_array($queryr)){
$Tid=$row['Tid']; 获得 $Tid
$Rdate=$row['Rdate'];
$til="select * from topic where Tid='$Tid'";
$rs=$obj->fetchrow($til);
$Title=$rs->Title;
$Tdate=$rs->Tdate;
$Tcontent=$rs->Tcontent;
$type=$rs->type;
$Ud=$rs->Uid; //发帖人的uid
$Un="select nicheng from users where Uid='$Ud'";
$rs=$obj->fetchrow($Un);
$Uname=$rs->nicheng;
像这种三个表reply、topic、users同时查询可以吗?