如何在下一个查询中使用选择选项值作为 PHP 变量？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/18875332/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How to use a select option value as a PHP variable in the next query?
提问by andy
I have the following code which provides a drop down list of all the rows in that specific table, this works fine. The code is below:
我有以下代码，它提供了该特定表中所有行的下拉列表，这很好用。代码如下：
<?php
$con=mysqli_connect("localhost","user","pass","db");
// Check connection
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$result = mysqli_query($con,"SELECT ID, NAME FROM b_sonet_group ORDER BY ID DESC");
echo "<select>";
echo "<option value=''>Select Your Project</option>";
while($row = mysqli_fetch_array($result))
{
echo "<option value='" . $row['ID'] . "'>" . $row['NAME'] . "</option>";
}
echo "</select>";
mysqli_close($con);
?>
I now want a second drop down list that is determined by what ever is selected in the one above based on the ID. So, I want something like:
我现在想要第二个下拉列表，该列表由根据 ID 选择的内容确定。所以，我想要这样的东西：
$result2 = mysqli_query($con,"SELECT ID, ALBUM_NAME FROM a_different_table WHERE ID=ID_FROM_QUERY_ABOVE");
echo "<select>";
echo "<option value=''>Select Your Album</option>";
while($row = mysqli_fetch_array($result))
{
echo "<option value='" . $row['ID'] . "'>" . $row['ALBUM_NAME'] . "</option>";
}
echo "</select>";
mysqli_close($con);
?>
I basically want to get the ID from the first drop down to provide the results in the second dropdown. Can this be done?
我基本上想从第一个下拉列表中获取 ID 以在第二个下拉列表中提供结果。这能做到吗？
回答by Robert
You can't "only" do this with Ajax, but you should do it with Ajax.
你不能“只”用 Ajax 来做到这一点，但你应该用 Ajax 做到这一点。
PHP way (not suggested, and untested). Basically use isset and if it is, more will be added to the form. The POST from the select, is the select name. So change the plain select tag which I did in the example below. This also requires them to submit it.
PHP方式（不建议，未经测试）。基本上使用isset，如果是，更多将添加到表单中。来自选择的 POST 是选择名称。因此，更改我在下面的示例中所做的普通选择标记。这也要求他们提交。
$result = mysqli_query($con,"SELECT ID, NAME FROM b_sonet_group ORDER BY ID DESC");
echo '<form id="project_form" method="post">';
echo "<select id='select_your_project' name = 'select_your_project'>";
echo "<option value=''>Select Your Project</option>";
while($row = mysqli_fetch_array($result))
{
echo "<option value='" . $row['ID'] . "'>" . $row['NAME'] . "</option>";
}
echo "</select>";
if(isset($_POST['select_your_project'])){
$result2 = mysqli_query($con,"SELECT ID, ALBUM_NAME FROM a_different_table WHERE ID='".$_POST['select_your_project']."'");
echo "<select id='select_your_album' name = 'select_your_album'>";
echo "<option value=''>Select Your Album</option>";
while($row = mysqli_fetch_array($result2))
{
echo "<option value='" . $row['ID'] . "'>" . $row['ALBUM_NAME'] . "</option>";
}
echo "</select>";
}
echo '<input type="submit" value="Submit">';
echo '</form>';
if(isset($_POST['select_your_album'])){
//do form submitted stuff here
}
Ajax way (two separate files, untested but gives you the idea)
Ajax 方式（两个单独的文件，未经测试但给了你想法）
//Main page (view) START
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
<script>
//this will trigger automatically when they change the first select box
$('#select_your_project').on('change', function(event){
if($(this).val() == 'select_your_project'){
$("#ajax_reply_div").empty()
}else{
var values = $(this).serialize();
$.ajax({
url: "php_data_file.php",
type: "post",
data: values,
success: function(data){
$("#ajax_reply_div").empty().append(data);
},
error:function(){
$("#ajax_reply_div").empty().append('something went wrong');
}
});
}
});
</script>
<form id="id_of_form">
<?php
echo "<select id='select_your_project' name='select_your_project'>";
echo "<option value='select_your_project'>Select Your Project</option>";
while($row = mysqli_fetch_array($result))
{
echo "<option value='" . $row['ID'] . "'>" . $row['NAME'] . "</option>";
}
echo "</select>";
?>
</select>
<div id="ajax_reply_div">
</div>
<input type="submit" value="Submit">
</form>
//Main page (view) END
//php_data_file.php START
if(isset($_POST['select_your_project'])){
$result2 = mysqli_query($con,"SELECT ID, ALBUM_NAME FROM a_different_table WHERE ID='".$_POST['select_your_project']."'");
//as a note it is better to only send an array back then build the HTML with jQuery, but this way is easier if you are new to jQuery/Ajax
echo "<select id='select_your_album' name = 'select_your_album'>";
echo "<option value=''>Select Your Album</option>";
while($row = mysqli_fetch_array($result2)){
echo "<option value='" . $row['ID'] . "'>" . $row['ALBUM_NAME'] . "</option>";
}
echo "</select>";
}
//php_data_file.php END
