count（）方法是否返回雄辩的集合中的项目计数或直接从sql查询中计数行

Question

I have the following two methods to count number of accounts that have active status. I want to know whether the count() method for model fetches rows from database and count the number of returned objects or will it just fetch row counts by applying SQL count() function. And also if the following two methods are similar or not?

Account::select(DB::raw('count(*) as count'))->where('status','active')->get()->count

Account::where('status','active')->count()

Answer 1

If you use it on a query builder, then it will perform an SQL query, but if you use it on a Laravel collection, it will perform it on the collection.

From your examples, this one will be a query:

Account::where('status','active')->count();
// SQL performed: SELECT count(*) FROM accounts WHERE status = active;

But this for example, would first fetch the results (which returns a collection) and then count the items in the collection:

Account::where('status','active')->get()->count();
// SQL performed: SELECT * FROM accounts WHERE status = active;

Maybe more intuitive:

$accounts = Account::where('status', 'active')->get();
// $accounts is now a collection of accounts SQL to get them was:
// select * from accounts where status = active;

// Then you can do this and it will be the same as performing count($accounts)
$count = $accounts->count();
// Same as doing this (except the items in the collection are different)
$count = collect(['some', 'elements', 'in the', 'collection']);