Laravel 5 - How to Query if DB Value is Array - laravel-5

Question

In database, I have "categories" and "products" table. In "products" table, there is a category_ids column which is an array, because the product has more than one categories.
What I want is to query the product that has category_ids of 1. I am trying to do like this, it is works, but I want a simpler way how to do.
$catId = 1; //category ID
$allProducts = Product::all(); // get all products
foreach ($allProducts as $product) { //loop all the products
if(in_array($catId, $product->category_ids)) { // check if category ID is in array of its product categories
$products[] = Product::find($product->id);
}
}
As you can see above,I must loop through all the products to check if category ID is exist in product categories array.
Is there a better way so it is not checking all the products?

Answer 1

All code is OK except one line .
$catId = 1; //category ID
$allProducts = Product::all(); // get all products
foreach ($allProducts as $product) { //loop all the products
$cats = explode(',',$product->category_ids);
if(in_array($catId, $cats)) { // check if category ID is in array of its product categories
$products[] = Product::find($product->id);
}
}
I added this line. I assume that multiple categories of a product will be stored in a single field with comma separated (Although its not the correct way, you need to create a M2M table)
$cats = explode(',',$product->category_ids);
So In in_array function, 2nd element should be an array. and Because of output of explode, $cats is an array.
in_array($catId, $cats)