Do - While loops in PHP - php

Question

I have what is probably a ridiculously simple problem to solve in PHP, but my brain will not engage.
I have products divided into categories. I have performed a successful query which gives me an array containing the products joined to their respective categories. Now I want to display them by category, splitting each category up into its own div. I have the following code:
$current_category = 0;
do
{
if($current_category != $row['category_id']){
echo '<div class="block">
<div class="menu">
<h4>'.$row['category_name'].'</h4>
<ul>';
do
{
echo '<li><a>'.$row['product_name'].'</a></li>';
}
while ($row['category_id'] == $current_category);
$current_category++;
//close list and divs
echo '</ul>
</div>
</div>';
}
}
while ($row = $stmt->fetch(PDO::FETCH_ASSOC));
But this only outputs the first product in each category, rather than outputting them all then moving on to the next. What am I doing wrong?

Answer 1

You need to get the next row in the inner loop, not in the outer one:
do {
// no need to check we're in the right category - we always are
$current_category = $row['category_id'];
echo '<div class="block">
<div class="menu">
<h4>'.$row['category_name'].'</h4>
<ul>';
do {
echo '<li><a>'.$row['product_name'].'</a></li>';
// !!! get the next row here
$row = $stmt->fetch(PDO::FETCH_ASSOC);
}
while ($row['category_id'] == $current_category);
//close list and divs
echo '</ul>
</div>
</div>';
// !!! and don't get it again here
} while ($row);
You need to make sure that your SQL query sorts by category first