MYSQL多库联合查询

1.给要用到的每个库都建立一个连接；
2.中间不要断开连接（如mysql_close($conn)）.

代码如下：

<?php
$dbconn1 = mysql_connect("localhost","root","admin888") or die("db1 error");
$db1 = mysql_select_db("db",$dbconn1) or die ("db1 select error");
$dbconn2 = mysql_connect("localhost","root","admin888") or die("db2 error");
$db2 = mysql_select_db("mydb",$dbconn2) or die("db2 select error");

$res = mysql_query("select * from db.t3 t join mydb.goods g on t.id=g.gid");
while($row = mysql_fetch_assoc($res)){
    var_dump($row);
}
?>