Laravel Eloquent sum of multiplied columns
Stefan Bogdanescu
Founder & Senior Architect · 2026-06-29
# Laravel Eloquent: Mastering the Sum of Multiplied Columns in SQL
As developers working with relational databases, we constantly face the challenge of aggregating data based on calculated fields. When using an Object-Relational Mapper (ORM) like Laravel Eloquent, the goal is often to translate complex database operations into clean, expressive PHP code. Today, we will tackle a common scenario: calculating the sum of the product of two columns (`jumlah` * `harga`) from a table, and understand why simple approaches often fail, leading us to the most robust solutions using Laravel's Query Builder capabilities.
This post will guide you through achieving the desired result—calculating `SUM(jumlah * harga)`—using idiomatic Laravel practices.
## The Challenge: Eloquent and Aggregation
You have a table named `transactions` with columns `jumlah` and `harga`. You want to execute a query equivalent to this SQL:
```sql
SELECT SUM(jumlah * harga) FROM transactions;
```
Your initial attempt, `$amount = Transaction::all()->sum('(jumlah * harga)')`, resulted in `0`. This happens because the Eloquent `sum()` method is designed to aggregate the values of an existing column (e.g., `->sum('column_name'`), not arbitrary mathematical expressions across the entire result set like this directly on a collection fetch. To perform complex arithmetic operations *before* summing, we must delegate that calculation entirely to the database engine.
## The Developer Solution: Leveraging the Query Builder
The most efficient and performant way to handle this is by utilizing Laravel's underlying Database facade or Eloquent's query builder to execute raw SQL functions directly against the database. This keeps the heavy lifting on the highly optimized MySQL server, rather than pulling large datasets into PHP memory only to calculate the sum later.
### Method 1: Using `DB::raw()` for Direct Aggregation
The cleanest approach is to use the `DB` facade and wrap our desired calculation inside a `SUM()` function using the `DB::raw()` method. This directly translates your desired SQL query into Laravel code.
```php
use Illuminate\Support\Facades\DB;
use App\Models\Transaction; // Assuming you are using an Eloquent model
class TransactionService
{
public function calculateTotalAmount()
{
$total = DB::table('transactions')
->sum(DB::raw('jumlah * harga'));
return $total;
}
}
// Example usage:
// $service = new TransactionService();
// $amount = $service->calculateTotalAmount(); // This returns 9000000
```
**Why this works:** By using `DB::raw('jumlah * harga')` inside the `sum()` method, you are instructing the database to calculate the product for every row first, and *then* sum those products. This is significantly faster than fetching all rows and calculating the multiplication in PHP. For more advanced ORM features, understanding how Laravel interacts with the underlying SQL is key, which is fundamental to mastering tools like those provided by [laravelcompany.com](https://laravelcompany.com).
### Method 2: Selecting and Summing (More verbose but flexible)
If you needed to retrieve both the calculated sum *and* perhaps other related data in a single query, you would use standard `select()` statements combined with aggregation functions.
```php
use App\Models\Transaction;
$result = Transaction::select(DB::raw('SUM(jumlah * harga) as total_amount'))
->first();
// $result will contain an object where 'total_amount' is the calculated sum.
```
This method allows you to retrieve the aggregated value along with other necessary data, making it highly flexible for complex reporting needs.
## Conclusion
Calculating derived sums across tables is a perfect example of where the power of the Eloquent ORM shines when combined with raw database functionality. Avoid trying to force PHP to perform complex mathematical aggregations on large result sets. Instead, delegate this task directly to MySQL using `DB::raw()`. This results in code that is not only cleaner and