Laravel count column of related model - laravel

Question

I want to count the number of upvotes and downvotes from ScripRating for a certain Script.
Script.php:
public function ratings()
{
return $this->hasMany('ScriptRating');
}
ScriptRating.php:
public function script()
{
return $this->belongsTo('Script');
}
The script_rating database table:
id (primary, increments)
script_id(integer)
rating(integer) <-- Can be either 1 (upvote) or -1 (downvote)
To retrieve a script and display the ratings:
$script = Script::where('title', '=', $title)->get();
{{ $script->ratings }}
This works fine, it returns an array: [{"id":1,"script_id":1,"rating":1}]. But at this point I'm stuck. How could I count the total upvotes and downvotes for a certain script?
I also have one more small question what I'm finding confusing. This does the same as the code above:
$script = Script::where('title', '=', $title)->with('ratings')->get();
{{ $script->ratings }}
What is the difference between these two methods and which one should I use?
Thanks in advance!
Edit
I made three scopes:
public function scopeTotalRating($query, $scriptId) {
return $query->where('script_id', $scriptId)->get()->sum('rating');
}
public function scopeThumbsUp($query, $scriptId) {
return $query->where('script_id', $scriptId)->having('rating', '=', 1)->get()->sum('rating');
}
public function scopeThumbsDown($query, $scriptId) {
return $query->where('script_id', $scriptId)->having('rating', '=', -1)->get()->sum('rating');
}
And display them as following:
{{ ScriptRating::thumbsUp($script->id) }}

Answer 1

You can use
{{ $script->ratings->count() }}
This will display the number total ratings a script has.
However what you're interested in doing is grouping the ratings into upvotes and downvotes, so you'll need to query your relationship by a group by clause.
Script::where('title', '=', $title)->with([
'ratings' => function($query) {
$query->groupBy('rating');
})
])->get();
I believe the collection returned should be now grouped by 1 and -1. Let me know of the results!
EDIT: You can also take a look here at the documentation on querying relationships:
http://laravel.com/docs/4.2/eloquent#querying-relations
EDIT for response:
The simplest way to do this without using group by would be separate queries:
$script = Script::where('title', $title)->first();
if ($script) {
$upvotes = ScriptRating::where('script_id', $script->id)->having('rating', '>', 0)->get()->count();
$downvotes = ScriptRating::where('script_id', $script->id)->having('rating', '<', 0)->get()->count();
}
Also the difference between your scripts mentioned is called eager loading or lazy loading. When you specify ->with() in your query, this is called eager loading. If you don't do this, the query will be ran when you specify $script->ratings
More about eager/lazy loading here:
http://laravel.com/docs/4.2/eloquent#eager-loading
Edit for another response:
You would use the ->whereHas('ratings') function if you want to gather scripts that only have ratings. You can also check the existence of the script having ratings by doing an if statement:
if ($script->ratings->count() > 0) {
// The script has ratings
} else {
// The script does not have ratings
}
If you don't want to keep repeating this code you could always put a function inside your Script.php model by using the following:
public function hasRatings()
{
return $this->ratings->count() > 0;
}
Then you can do:
if ($script->hasRatings())

Answer 2

You can add to the Script model class those 2 functions:
public function ratingsSumRelation()
{
return $this->hasOne('ScriptRating')->selectRaw('script_id, sum(rating) as sum_all')
->groupBy('script_id');
}
public function getRatingSumAttribute()
{
return $this->ratingsSumRelation ?
$this->ratingsSumRelation->sum_all: 0;
}
and now display sum using:
{{ $script->rating_sum }}