Level 102
Set up two relationships and load both. https://laravel.com/docs/9.x/eloquent-relationships#has-one-of-many
Oct 26, 2022
6
Level 2
Optimising Eloquent Query with Relationship
I have ~500 users whom each have a new metrics row added to the DB each day.
I was running a query to find the difference between a value from their first entry and their last.
I decided to eager load the relationship to cut down on DB calls.
Something like...
$users = User::with('metrics')->get();
foreach ($users as $user) {
$difference = $user->metrics->last()->value - $user->metrics->first()->value;
}
The problem with this approach is it loads all the user metrics models which is a drain on memory.
Is there a better approach to optimise the query?
Level 2
@Sinnbeck thanks.
I tried...
$users = User::with(['latestMetric','oldestMetric'])->get();
foreach ($users as $user) {
$difference = $user->latestMetric()->first()->followers_count - $user->oldestMetric()->first()->followers_count;
}
The page become unresponsive.
I'll have another play around with it.
Level 102
@brandymedia remove ->first() as you are only getting 1
Level 2
$user->latestMetric()->followers_count - $user->oldestMetric()->followers_count
Gives this error...
Undefined property: Illuminate\Database\Eloquent\Relations\HasOne::$followers_count
Level 2
Changed to...
$user->latestMetric->followers_count - $user->oldestMetric->followers_count
I.e. without the parenthesis.
Looks like I'm in business.
Thanks for the help 👍
Level 102
@brandymedia happy to help :)
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