怎的同时查询多个数据表

Quote: 引用:

单个

$result1 = mysql_query("select * from jtrb1 where name='上衣' and price < 300");
$row1 = mysql_fetch_array($result1);

$result2 = mysql_query("select * from jtrb2 where name='上衣' and price < 300");
$row2 = mysql_fetch_array($result1);

$result3 = mysql_query("select * from jtrb3 where name='上衣' and price < 300");
$row3 = mysql_fetch_array($result3);

组合

select * from jtrb1,jtrb2,jtrb3 
where jtrb1.name='上衣' and jtrb1.price < 300
and   jtrb2.name='上衣' and jtrb2.price < 300
and   jtrb3.name='上衣' and jtrb3.price < 300

组合这里，在数据库里查询，3个数据库里都有一条相同的记录，但它只列出一条，我想把三条都列出来，这里要怎么写？
还有

$con = mysql_connect("localhost","root","");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }
mysql_select_db("test", $con);
$query="SELECT * FROM jtrb1,jtrb2,jtrb3 WHERE jtrb1.name='上衣' and jtrb2.name='上衣' and jtrb3.name='上衣'";
$result= mysql_query($query,$con)or die(mysql_error());
$row= mysql_fetch_array($result);
while($row)
  {
	  echo $row['jtrb1.Name']."
";
	  //下面省略
  }
  mysql_close();
?>

我这样子写输出空白。请大神指点。