先提几点建议：
- mysql 已折旧，您应该转到 PDO 准备好的语句或 mysqli。您可以查阅 php 手册。
- 注释您的代码，除非您从上到下阅读，否则您无法跟进。
现在进入您的代码：
<?php
// Start document with includes needed, header, connection, functions.
require_once('../includes/header.php');
require_once('../includes/connection.php');
include('../includes/get_username.php');
include('sanitise.php');
// Start with the month variable posted from $_GET, this will begin the initial display.
$month = sanitise($_GET['month']);
?>
<!-- Begin Table Display and Layout -->
<table id="contentbox">
<tr>
<td>
<?php // Open PHP Tag to get variables to display in the table
$color="1";
// Initial Query to get the data for the month passed by GET, ordering by dv_id.
$qry = mysql_query("SELECT * FROM tbl_dv WHERE monthname(date_added) = '$month' ORDER BY dv_id DESC");
// Format the table rows for display
echo "<table class='dvr_table' id='alternatecolor' width='100%'>
<tr>
<th>DATE ADDED</th>
<th>CT</th>
<th>PAYEE</th>
<th>PARTICULAR</th>
<th>PM</th>
<th>VOUCHER NO.</th>
<th>NET</th>
<th>OBR NO.</th>
<th>";
// Fill the SELECT option with all the RESPO/Office data
$sql = "SELECT respo FROM tbl_dv WHERE monthname(date_added) = '$month' GROUP BY respo";
$result = mysql_query($sql);
// Display the select with the newly populated content
echo "<select name='respo'>
<option value=' ' disabled='disabled' selected='selected'>Select a RESPO/Office</option>";
// While the result contains data we will display respo as a select option.
while ($row = mysql_fetch_array($result)) {
echo "<option value='" . $row['respo'] . "'>" . $row['respo'] . "</option>";
}
// Finish the table header
echo "</th>
<th>ACCOUNT CODE</th>
<th>FPP CODE</th>
<th>DEDUCTION</th>
</tr>";
// While we have data from the original query we will display it
while ($row = mysql_fetch_array($qry)) {
$dv_id = $row['dv_id']; // grab the dv_id
if($color==1){ // Setup color scheme
echo "<tr bgcolor='#ffffff'> // Color for the row
// Let's begin filling the table with data
<td style='text-align:center;'>" .date_format(date_create($row['date_added']), 'm/d/y')." </td>
<td style='text-align:center;'>" .$row['cashtype']."</td>
etc.......
$color="2";
} else {
echo "<tr bgcolor='#ebeaea'>
<td style='text-align:center;'>" .date_format(date_create($row['date_added']), 'm/d/y')." </td>
<td style='text-align:center;'>" .$row['cashtype']."</td>
etc......
$color="1";
}
}
echo "</tr>";
?>
查看上述代码后，很明显您尚未设置查询来根据所选选项过滤您正在显示的数据。
您的第一个查询：
// Initial Query to get the data for the month passed by GET, ordering by dv_id.
$qry = mysql_query("SELECT * FROM tbl_dv WHERE monthname(date_added) = '$month' ORDER BY dv_id DESC");
您可以为所选选项附加一个新变量，展开您的WHERE语句。WHERE monthname(date_added) = '$month' && respo = '$respo'并将此查询移到 select 选项之后，以便它可以访问 select 选项选择的值。最后，除非您打算使用 jQuery 来处理选择框更改值，否则您需要一个提交按钮来显示选择选项的状态更改。
伪代码：
检查提交
在查询 WHERE 子句中更改部门的值
显示请求的数据
这应该使您朝着实现预期结果所需的方向前进。
编辑：
在您发布的第三个答案中：
$viewrecord = "SELECT * FROM tbl_dv WHERE respo='".mysql_real_escape_string($respo)."' AND year(date_added)='$year' GROUP BY date_added ";
您说它没有按传入的月份进行过滤，您没有将其添加到查询中，特别是 WHERE 子句。所以应该是：
$viewrecord = "SELECT * FROM tbl_dv WHERE respo='".mysql_real_escape_string($respo)."' AND month(month_added)='$month' AND year(date_added)='$year' GROUP BY date_added ";
最终编辑：
您的第一个问题源于未将$_GET['date_added']值发送到视图页面，因此您将永远不会显示任何内容。正确格式化选择框并从数据库中添加 RESP 和日期数据的数据：
echo "<option value='". $row['respo'] . "+". $row['date_added'] . "'>" . $row['respo'] . " (".$row['count(*)'].")</option>";
现在我们传递了 respo 和日期字符串，我们可以处理下一页上的数据：
/* UNCOMMENT NEXT LINE FOR ERROR DETECTION */
//error_reporting( E_ALL );
/* GET THE ENTIRE STRING PASSED FROM THE SELECT OPTION */
$respo = $_GET['respo'];
/* EXPLODE THE DATA BY + SYMBOL TO GET THE DATA */
$data = explode("+", $respo);
/* FORMAT THE DATETIME FROM THE STRING TO A FRIENDLY FORMAT */
$month = date("m", strtotime($data[1])) . "<br />";
$year = date("Y", strtotime($data[1])) . "<br />";
这就是我选择使用数据并获得所需内容的方式，所以现在查询将是：
$viewrecord = "SELECT * FROM tbl_dv WHERE respo='".mysql_real_escape_string($data[0])."' && year(date_added)='$year' && month(date_added)='$month' ";
这将仅显示RESPO and the date by year and month通过 传入页面的记录$_GET。