Filter not filtering - php

Question

I am trying to make a filter for website of cars. I would like to be able to filter by color of car represented by exterior. I do this by Select Distinct from exterior colors to list all of the exterior colors.
<h6 class="text-info">Select Color</h6>
<ul class="list-group">
<?php
$sql="SELECT DISTINCT exterior FROM newcars ORDER BY exterior";
$result=$conn->query($sql);
while($row=$result->fetch_assoc()) {
?>
<li class="list-group-item">
<div class="form-check">
<label class="form-check-label">
<input type="checkbox" class="form-check-input product_check" name="" value="<?= $row['exterior']; ?>" id="exterior"><?= $row['exterior']; ?>
</label>
</div>
</li>
<?php
}
?>
</ul>
<div id="test">
<?php
$sql = "SELECT * FROM newcars";
$result = mysqli_query($conn, $sql);
if (mysqli_num_rows($result) > 0) {
while ($row = mysqli_fetch_assoc($result)) {
echo ("<a href='newcarindex.php?id={$row['id']}'><div class='car'>");
echo '
<tr>
<td>
<img src="data:image\jpeg;base64,'.base64_encode($row['photo']).'"/>
</td>
</tr>
';
echo "<h2 class=car-name>";
echo $row['name'];
echo "</h2>";
echo "<span class=stock>STOCK#";
echo $row['stock'];
echo "</span>";
echo "<h3 class=car-msrp>";
echo $row['msrp'];
echo "</h3>";
echo "</div></a>";
}
} else {
echo "There are no Comments!";
}
?>
</div>
action.php this page i link to get the the results from what color they select. But I still cannot get it filter to the results.
include 'dbh.php';
if(isset($_POST['action'])) {
$sql = "SELECT * FROM newcars WHERE class !=''";
if(isset($_POST['class'])) {
$class = implode("','", $_POST['class']);
$sql .="AND class IN('".$class."')";
}
if(isset($_POST['body'])) {
$body = implode("','", $_POST['body']);
$sql .="AND class IN('".$body."')";
}
if(isset($_POST['exterior'])) {
$exterior = implode("','", $_POST['exterior']);
$sql .="AND class IN('".$exterior."')";
}
$result = $conn->query($sql);
$output='';
if($result->num_rows>0){
while($row=$result->fetch_assoc()){
$output .='<a href='newcarindex.php?id={$row['id']}'><div class='car'>
<tr>
<td>
<img src="data:image\jpeg;base64,'.base64_encode($row['photo']).'"/>
</td>
</tr>
<h2 class=car-name>'.$row['name'].'</h2>
<span class=stock>STOCK#'.$row['stock'].'</span>
<h3 class=car-msrp>'.$row['msrp'].'</h3>
</div></a>'
}
} else {
$output ="<h3>No Results</h3>";
}
echo $output;
}
?>

Answer 1

First of all you need to wrap your checkboxes in a HTML form that will send data to action.php file:
<h6 class="text-info">Select Color</h6>
<form action="action.php">
<ul class="list-group">
<?php
$sql = "SELECT DISTINCT exterior FROM newcars ORDER BY exterior";
$result = $conn->query($sql);
while($row=$result->fetch_assoc()) {
?>
<li class="list-group-item">
<div class="form-check">
<label class="form-check-label">
<input type="checkbox" class="form-check-input product_check" name="" value="<?= $row['exterior']; ?>" id="exterior"><?= $row['exterior']; ?>
</label>
</div>
</li>
<?php
}
?>
</ul>
<input type="submit" value="Filter" />
</form>
<div id="test">
...
Then, in action.php file you need to revise your SQL query. At this moment, when you concatenate base $sql variable with the one from if(isset($_POST['exterior'])) condition, the query looks like:
SELECT * FROM newcars WHERE class !=''AND class IN( ...
making it invalid (notice no space between !='' and AND).
Then the while loop has mixed apostrophes and quotation marks, which makes PHP code invalid. It should look like this:
while($row=$result->fetch_assoc()){
$photo = base64_encode($row['photo']);
$output .= "<a href='newcarindex.php?id={$row['id']}'>
<div class='car'>
<tr>
<td>
<img src='data:image\jpeg;base64,{$photo}'/>
</td>
</tr>
<h2 class='car-name'>{$row['name']}</h2>
<span class='stock'>STOCK#{$row['stock']}</span>
<h3 class='car-msrp'>{$row['msrp']}</h3>
</div></a>";
}