按国家过滤来自mysql的数据

Question

I want to filter my data by countries from a dropdown menu:

<form name="filter_form" method="POST" action="display_data.php">
Select a country:
<select name="value">
    <option name="country" value="AU">Austria</option>
    <option name="country" value="BE">Belgium</option>
    <option name="country" value="BU">Bulgaria</option>
</select>
<input type="submit" name="btn_submit" value="Submit Filter" />
<?php
if($_POST['country'] == 'BE') {  

    $query = mysql_query("SELECT * FROM think WHERE Country='Belgium'");  
}  
elseif($_POST['country'] == 'AU') { 
 $query = mysql_query("SELECT * FROM think WHERE Country='Austria'");  
} else {  
    $query = mysql_query("SELECT * FROM think");  
}  
?>

The code does not filter any data. If anyone can help, thanks!

Answer 1

When you use select tag, the Server page will refer name of select tag and not option.

Change your code as below:

<select name="country">
    <option value="AU">Austria</option>
    <option value="BE">Belgium</option>
    <option value="BU">Bulgaria</option>
</select>

Answer 2

if($_POST['country'] == 'BE') {  

should be

if($_POST['value'] == 'BE') {  

And so on for others !!

Answer 3

You need to change the location of the name attribute. You now have it on the option element but it needs to be on the select element.

<form name="filter_form" method="POST" action="display_data.php">
Select a country:
<select name="country">
    <option value="AU">Austria</option>
    <option value="BE">Belgium</option>
    <option value="BU">Bulgaria</option>
</select>
<input type="submit" name="btn_submit" value="Submit Filter" />
<?php
if($_POST['country'] == 'BE') {  

    $query = mysql_query("SELECT * FROM think WHERE Country='Belgium'");  
}  
elseif($_POST['country'] == 'AU') { 
 $query = mysql_query("SELECT * FROM think WHERE Country='Austria'");  
} else {  
    $query = mysql_query("SELECT * FROM think");  
}  
?>

Answer 4

Avoid writing redundant code. Change your code with below code:

<form name="filter_form" method="POST" action="display_data.php">
Select a country:
<select name="country">
    <option value="AU">Austria</option>
    <option value="BE">Belgium</option>
    <option value="BU">Bulgaria</option>
</select>
<input type="submit" name="btn_submit" value="Submit Filter" />

<?php
if(isset($_POST['country']))
{
    switch($_POST['country'])
    {
    case 'BE' : $countryName = 'Belgium';
                break;
    case 'AU' : $countryName = 'Austria';
                break;
    default : $countryName = '';
              break;
    }
    $where = '';
    if($countryName != '')
    {
        $where = "WHERE Country='".$countryName."'";
    }   
    $query = mysql_query("SELECT * FROM think ".$where."");  
}
?>