Laravel: Sum daily (groupby date) then retain date with empty rows - laravel

Question

stackoverflow,
I have working laravel function which get the daily sum of sales for the last 30 days.
I will use the data to build a graph, so I need to get the dates even if its empty and give them a value of "0" as their sum.
here's my code (it's working but only returns dates which are not empty)
public function getDaily() {
$startDate = Carbon::now()->subDays(30);
$endDate = Carbon::now();
$all_dates = array();
for($i = 0;$i<=30;$i++)
{
$all_dates[] = $startDate->toDateString();
$startDate->addDay();
$sales=DB::table('sale_details')
->select(DB::raw('sum(amount_due) as daily'),DB::raw('date(created_at) as date'))
->groupBy('date')
->orderBy('date','desc')
->get();
}
return $sales;
}

Answer 1

To get array of objects you may use good Collection's methods:
$sales = DB::table('sale_details')
->whereBetween('created_at', [$startDate, $endDate])
->select([
DB::raw('sum(amount_due) as daily'),
DB::raw('date(created_at) as date'),
])
->groupBy('date')
->get()
->keyBy('date');
$period = new CarbonPeriod($startDate, '1 day', $endDate);
// Fill zeroes
foreach ($period as $date) {
$dateString = $date->toDateString();
if (!$sales->has($dateString)) {
$sales->put($dateString, ['date' => $dateString, 'daily' => 0]);
}
}
// Convert to associative array
$sales = $sales->values()->toArray();

Answer 2

Try this:
$sales = DB::table('sale_details')
->whereBetween('created_at', [$startDate, $endDate])
->select([
DB::raw('sum(amount_due) as daily'),
DB::raw('date(created_at) as date'),
])
->groupBy('date')
->orderBy('date','desc')
->pluck('daily', 'date')
->toArray();
$period = new CarbonPeriod($startDate, '1 day', $endDate);
// Fill zeroes
foreach ($period as $date) {
if (!isset($sales[$date->toDateString()])) {
$sales[$date->toDateString()] = 0;
}
}
Another solution is using database-generated series of dates (pgsql example: Generating time series between two dates in PostgreSQL) and join it with result.