How do pathfinder options -> Hard Mix and Soft Mix effects work?

Question

Adobe Illustrator

In what cases can they be applied?

Answer 1

If you haven't done so, there should be a field in the video table structure that links them to a particular category.
Then we get the categories from the database:

$categories = mysqli_query($connection,"SELECT * FROM `category`");
$categoriesArr = array();
while($cat = mysqli_fetch_assoc($categories)){
//образуйте, например, массив с ними:
$categoriesArr[] = $cat['category']; //не знаю в каком виде они у вас хранятся в таблице
}

What you have already done and are already working with them:

foreach($categoriesArr as $cat){
//для каждой категории делаем запрос в бд
$videos = mysqli_query($connection, "SELECT * FROM `videos` WHERE category = '$cat' ");
//и вывод видео
while($video = mysqli_fetch_assoc($videos)){
...
}
}