Giải bài tập PHP

Bài ̀4

<?php
$host = '192.168.43.99';
$username = 'root';
$passwd = 'root';
$dbname = 'shop';
$conn = new mysqli($host, $username, $passwd, $dbname);

$query = "SELECT * FROM category order by name";

$data = $conn->query($query);
$newline = '<br/>';

echo "<form method='GET'>";
echo "<select id='category_list' name='cat_id' onchange='this.form.submit()'>";
echo "<option>Tất cả</option>";
while ($row = $data->fetch_assoc()) {
    $id = $row['Id'];
    $name = $row['Name'];
    echo "<option value='$id'>";
    echo "$name";
    echo "</option>";
}
echo "</select>";
echo "</form>";

if (isset($_GET['cat_id'])) {
    $cat_id = $_GET['cat_id'];
    $query = "SELECT p.id, p.Name, c.Name as Cat_name, p.Description, p.Price, p.Is_active
        from product p join category c
	on p.Cat_id = c.Id
        where p.cat_id = $cat_id
    order by p.Name";
} else {
    $query = "SELECT p.id, p.Name, c.Name as Cat_name, p.Description, p.Price, p.Is_active
        from product p join category c
	on p.Cat_id = c.Id       
    order by p.Name";
}

$data = $conn->query($query);
echo "<table>
    <thead>
        <tr>
            <th>Name</th>  
            <th>Category</th>
            <th>Description</th>
            <th>Price</th>
            <th>Active</th>
        </tr>
    </thead>
    <tbody>";
while ($row = $data->fetch_assoc()) {
    $name = $row['Name'];
    $cname = $row['Cat_name'];
    $des = $row['Description'];
    $price = $row['Price'];
    $is_active = $row['Is_active'];

    if ($is_active) {
        $active = "<input type='checkbox' checked disabled>";
    } else {
        $active = "<input type='checkbox' disabled>";
    }

    echo "<tr>
                <td>$name</td>  
                <td>$cname</td>
                <td>$des</td>
                <td>$price</td> 
                <td>$active</td>
            </tr>";
}

echo "</tbody></table>";

$conn->close();
?>

<style>
    table, thead, tbody, tr, th, td{
        border: 1px solid black;
    }

</style>