Laravel Query Builder - sum() method issue

Question

I'm new to laravel and I have some issues with the query builder. The query I would like to build is this one:

SELECT SUM(transactions.amount)
FROM transactions
JOIN categories
ON transactions.category_id == categories.id 
WHERE categories.kind == "1"

I tried building this but it isn't working and I can't figure out where I am wrong.

$purchases = DB::table('transactions')->sum('transactions.amount')
    ->join('categories', 'transactions.category_id', '=', 'categories.id')
    ->where('categories.kind', '=', 1)
    ->select('transactions.amount')
    ->get();

I would like to get all the transactions that have the attribute "kind" equal to 1 and save it in a variable. Here's the db structure:

transactions(id, name, amount, category_id)

categories(id, name, kind)

Dick

Answer 1

You don't need to use select() or get() when using the aggregate method as sum:

$purchases = DB::table('transactions')
    ->join('categories', 'transactions.category_id', '=', 'categories.id')
    ->where('categories.kind', '=', 1)
    ->sum('transactions.amount');

Read more: http://laravel.com/docs/5.0/queries#aggregates

Impi

I am so sorry! I didn't knew I had to do that, I'm a newbie in stackoverflow! I am having other issues in my code, and maybe you can help me out. Sorry but I don't really get laravel query building methods. I have this query, which takes all the transactions that have categories with the kind equal to 1 and then I print the results to show them to the user. The problem is that all users can see them! The relations between the main tables are good, I guess something is wrong with the query, probably I should get the transactions created by the connected user. What should I change? – Dick

Here's the query: '$purchases = DB::table('transactions')->select('transactions.id', 'transactions.name', 'amount', 'description', 'date', 'category_id') ->join('categories', 'transactions.category_id', '=', 'categories.id') ->where('categories.kind', '=', 1) ->get();' – Dick

It is worth noting that sum() needs to be at the end of the command - otherwise it will error with the your next function being called on a string (for example) sum()->groupBy('price') would throw (Laravel 8): Call to a member function groupBy() on string – Surge

Answer 2

If one needs to select SUM of a column along with a normal selection of other columns, you can sum select that column using DB::raw method:

DB::table('table_name')
    ->select('column_str_1', 'column_str_2', DB::raw('SUM(column_int_1) AS sum_of_1'))
    ->get();

Britska

Answer 3

You can get some of any column in Laravel query builder/Eloquent as below.

$data=Model::where('user_id','=',$id)->sum('movement');
return $data;

You may add any condition to your record. Thanks

Cole

Answer 4

MyModel::where('user_id', $_some_id)->sum('amount')

Bdellium