在mysql_query函数中指定所用连接，即：

<?php

$conn1 = mysql_connect("127.0.0.1", "root","root","db1");

mysql_select_db("Muma", $conn1);

$conn2 = mysql_connect("127.0.0.1", "root","root","db2");

mysql_select_db("product", $conn2);



$sql = "select * from ip";

$query = mysql_query($sql,$conn1); //添加连接$conn1

if($row = mysql_fetch_array($query))

echo $row[0]."\n";



$sql = "select * from web ";

$query = mysql_query($sql, $conn2);

if($row = mysql_fetch_array($query))

echo $row[0];

?>