Laravel Convert Mysql query to Eloquent - sql

Question

I'm new to Laravel and I can write simple eloquent queries but have no idea how to convert this query to eloquent. Can anyone give any idea, is it possible to convert this to eloquent or I have to write raw query?
"Select categories.id, categories.name, Sum(likes.liked) as liked
FROM categories, likes
WHERE likes.material_id IN (SELECT category_material.material_id
FROM category_material
WHERE category_material.category_id = categories.id)
GROUP BY categories.id";
Here my Models
class Material extends Model
{
public function categories(){
return $this->belongsToMany(Category::class,'category_material');
}
public function likes(){
return $this->hasMany(Like::class);
}
////////////////////////////////////////////////////////////
class Like extends Model
{
protected $table = 'likes';
public function user(){
return $this->belongsTo(User::class);
}
public function material(){
return $this->belongsTo(Material::class);
}
//////////////////////////////////////////////////////
class Category extends Model
{
public function materials(){
return $this->belongsToMany(Material::class,'category_material');
}

Answer 1

You can define a likes relationship in your Category model like so:
public function likes()
{
return $this->belongsToMany(Like::class, 'category_material', 'category_id', 'material_id', 'id', 'material_id');
}
Then to achieve what you're after with Eloquent you can use a mixture of has() and withCount, however, we're going to modify the withCount call to return a sum() instead:
$catrgories = Category::has('likes')->withCount([
'likes as liked' => function ($query) {
$query->select(DB::raw('SUM(likes.liked)'));
},
])->get();
If you're wanting to return categories that don't have any likes you can remove the has() method, and introduce the COALESCE() function to your raw query:
$catrgories = Category::withCount([
'likes as liked' => function ($query) {
$query->select(DB::raw('COALESCE(SUM(likes.liked), 0)'));
},
])->get();
Alternatively, you could simply load the necessary relationships and then use that fact that Eloquent returns collection to get the value after you've retrieved the results from the database:
$categories = Category::with('materials.likes')->get()->map(function ($item) {
$item->setAttribute('liked', $item->materials->map(function ($item) {
return $item->likes->map->sum('liked')->sum();
})->first());
$item->unsetRelation('materials');
return $item;
});
This would mean that you don't have to add the custom relationship.