How to get active class only in first div of carousel PHP

Friends thumb in the picture when the picture was selected, I could not do the Active incident.

<div id="carousel-product" class="carousel slide carousel-thumbnails mb-3" data-ride="carousel">
    <div class="carousel-inner" role="listbox">
        <?php
        $alt_img = '';
        $query = $db->query("SELECT * FROM urun_img WHERE urun_id = '{$urun['id']}'", PDO::FETCH_ASSOC);
        if($query->rowCount())
        {
            foreach($query as $row)
            {
                echo '<div class="carousel-item active"><img class="img-responsive" src="upload/'.$row['img'].'"></div>';
                $alt_img.= '<li data-target="#carousel-product" data-slide-to="1" class="verso-transition active"><img src="upload/'.$row['img'].'" alt="'.$urun['baslik'].'"></li>';
            }
        }
        ?>
    </div>
    <ol class="carousel-indicators -mb--2">
        <?php echo $alt_img; ?>
    </ol>
</div>

Solution

Inside your if statement, you could simply do this:

$row_count = 1;
foreach($query as $row)
{
    echo '<div class="carousel-item'; if($row_count == 1) { echo ' active'; } echo '"><img class="img-responsive" src="upload/'.$row['img'].'"></div>';
    $alt_img.= '<li data-target="#carousel-product" data-slide-to="1" class="verso-transition active"><img src="upload/'.$row['img'].'" alt="'.$urun['baslik'].'"></li>';
    $row_count++;
}

To explain this:

You create a $row_count variable with 1 at the value (this is the first row you're going to treat in your loop)
You create a condition to say "if this is the first row only, then we add the class"
You increment $row_count at the end of the loop, so for each new row, it will change its value to 2, then 3, then 4, etc... which then won't match the if($row_count == 1) condition.