Wrong way - easy to make mistake
Let's say we need to filter male customers aged 18+ or female customers aged 65+ (whatever the reason is, it's just a hypothetical example). Simple MySQL query would look something like this:... WHERE (gender = 'Male' and age >= 18) or (gender = 'Female' and age >= 65)Now let's transform it to Eloquent:
// ...
$q->where('gender', 'Male');
$q->orWhere('age', '>=', 18);
$q->where('gender', 'Female');
$q->orWhere('age', '>=', 65);
But wait, if we launch it like that, MySQL query wouldn't have any brackets and would be launches as this:
... WHERE gender = 'Male' and age >= 18 or gender = 'Female' and age >= 65Which is wrong order - it would actually be executed in this order:
... WHERE ((gender = 'Male' and age >= 18) or gender = 'Female') and age >= 65The worst thing is that it wouldn't throw any errors. And if you don't test properly, you wouldn't even notice that it filtered out wrong results.
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Right way - putting "brackets" into Eloquent
What we actually need here is a thing called Advanced Where Clauses - where we can assign a function to a where clause, like this:// ...
$q->where(function ($query) {
$query->where('gender', 'Male')
->where('age', '>=', 18);
})->orWhere(function($query) {
$query->where('gender', 'Female')
->where('age', '>=', 65);
})
This code will produce SQL query exactly like we need - with brackets in the right places.
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