PHP从表中选择数据，但无法工作

Question

好的，所以我并不真正了解PHP，当有人提交一个表单时，它需要检查这个日期时间戳是否已经在mysql表中了，然后再做一些事情。

localhost.php：

<?php 
$hostname_localhost = "localhost";
$database_localhost = "bookings";
$username_localhost = "username";
$password_localhost = "password";
$localhost = mysql_pconnect($hostname_localhost, $username_localhost, $password_localhost) or trigger_error(mysql_error(),E_USER_ERROR);
?>

主档案：

<?php require_once('../Connections/localhost.php'); ?>
<?php
$date = $_POST['date'];

$result = mysql_query("SELECT * FROM `bookingtable` WHERE `Date of Session` = '$date'");
if(mysql_num_rows($result) > 0) {
    echo 'the date was found, please try another';
} else {
    echo 'the date wasnt found';
};
?>

它曾经起作用，但现在它总是说，它不是在桌子上，当它真的是。

Answer 1

在localhost.php的末尾写下一行

mysql_select_db($database_localhost);

Answer 2

试试下面的代码：

Localhost.php

   <?php 
        $hostname_localhost = "localhost";
        $database_localhost = "bookings";
        $username_localhost = "username";
        $password_localhost = "password";
        $tablename_localhost = //your name of your table from database
        $localhost = mysql_pconnect($hostname_localhost, $username_localhost, $password_localhost, $tablename_localhost) or trigger_error(mysql_error(),E_USER_ERROR);
   ?>

Main.php

    <?php require_once('../Connections/localhost.php');


     $date = $_POST['date'];

     $result = mysql_query($localhost, "SELECT * FROM bookingtable WHERE Date of Session = '$date'");

     if(mysql_num_rows($result) > 0) {
         echo 'the date was found';
     } else {
          echo 'the date wasnt found';
     };
 ?>