得到错误的数据库不选择(Getting error database not selected)

码：

<?php
session_start();
$_SESSION['msg'] = "";
$con = mysql_connect('localhost','me','omglol');
mysql_select_db('test',$con);
$q = mysql_query(sprintf("select * from UserTable where (nick=\"%s\") AND (pass=SHA1(\"%s\"))",$_POST['nick'],$_POST['pass']),$con) or die(mysql_error());

这看起来我的权利。是的，我知道“测试”的存在。并包含用户表。

首先，去掉添加到PHP4我忘了标签谢谢:(

按照Laser_wizard的建议，我做了以下内容：（全部代码）：

<?php
session_start();
$_SESSION['msg'] = "";
$con = mysql_connect('localhost','me','omglol');
if(!$con)
{
    die("The connection to mysql server is not being made.");
}
$db = 'test';
$selected = mysql_select_db($db,$con);
if(!$selected)
{
    die(sprintf("Cannot use database %s.",$db));
}
//$q = mysql_query(sprintf("select * from UserTable where (nick=\"%s\") AND (pass=SHA1(\"%s\"))",$_POST['nick'],$_POST['pass']),$con) or die(mysql_error());
$q = mysql_query("select * from UserTable",$con) or die("The query statement still isn't working");
$row = mysql_fetch_assoc($q);
$dest=0;
if(mysql_num_rows($q)==0)
{
    //$testn = mysql_query(sprintf("select * from UserTable where nick=(\"%s\")",$_POST['nick']),$con);
        $testn = mysql_query("select * from Category",$con) or die("The 2nd query statement still isn't working");
        if(mysql_num_rows($testn)==0)
        {
               $_SESSION['msg'] = "Nick ".$_POST['nick']." was not found. Check spelling or <a href=\\\"register.php\\\">register</a>";
        }
        else
        {
                $_SESSION['msg'] = "Password incorrect";
        }
        if(isset($_SESSION['attempts']))
        {
                $_SESSION['attempts'] = $_SESSION['attempts'] + 1;
        }
        else
        {
                $_SESSION['attempts'] = 1;
        }
    mysql_free_result($q);
    mysql_free_result($testn);
        mysql_close($con);
    $dest = 'Location:http://cs4.sunyocc.edu/~me/onestopshop/login.php';
}
else
{
        $_SESSION['nick'] = $_POST['nick'];
    $_SESSION['email'] = $row['email'];
    mysql_free_result($q);
    mysql_close($con);
    $dest = 'Location:http://cs4.sunyocc.edu/~me/onestopshop/index.php';
}
header($dest);
exit();
?>

同样的错误如上。所以$ CON设置和$选择读取真实的，所以我很困惑接下来要检查什么。我猜mysql_select_db（$数据库，$ CON）; 也不是$ testn仍然没有工作，但还在读书真的吗？我很困惑，下一步要做什么。

Answer 1:

扔在一些模具语句来测试连接，并确保它的设置。除了比我想说注释掉查询网上看到，如果这是导致问题。

$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
    die('Not connected : ' . mysql_error());
}

// make foo the current db
$db_selected = mysql_select_db('foo', $link);
if (!$db_selected) {
    die ('Can\'t use foo : ' . mysql_error());
}

Answer 2:

如果你有PHP> = 5.1.0忘记了这些说明，并使用PDO：

<?php
    $conn = new PDO('mysql:host=localhost;dbname=test', 'user', 'pass');
    foreach($conn->query('SELECT * from TEST') as $row) {
        print_r($row);
    }
?>