how can i increment 6 months selecting from database to_date field? - laravel-5

Question

I'm making my project,and want to increment date from fetching to_date filed with 6 months if last to_date is gone then add more 6 months and so on what can i do for this?
$abc=(Session::get('email'));
$email= $request->input('email');
if (Maintenance::where('email', '=', $email)) {
$users=Carbon::create(2019,0,30)->addMonths(6)->toDatestring();
if (Maintenance::where('maintenance_status', '=', 'PAID')->orderBy('todate','DESC')) {
$check = Maintenance::select('to_date')->where('maintenance_status', '=', 'PAID')->orderBy('to_date','DESC')->get();
// $users= Carbon($check[0])->addmoths(6);
$users = Carbon::addMonths(6)->toDatestring();
i expect the output of 30-06-2019,30-12-2019 and so on but the actual output is only increment one time using Carbon and i want to increment fetching from database date

Answer 1

It looks like you are overwriting your variable instead of adding to it.
$users = Carbon\Carbon::create(2019,0,30)->addMonths(6)->toDatestring();
returns 2019-06-30.
$users = Carbon\Carbon::addMonths(6)->toDatestring(); would overwrite it, but it actually breaks "PHP Error: Call to a member function addMonths() on string".
Don't store the string as your variable. Instead, keep it as a instance of Carbon so that you can call functions on it. Then when you need to use it call toDatestring().
It would look something like this:
$date_to_increment = Carbon\Carbon::create(2019,0,30)->addMonths(6);
echo($date_to_increment->toDatestring()); // 2019-06-30
if ($your_condition) {
$date_to_increment->addMonths(6);
echo($date_to_increment->toDatestring()); // 2019-12-30
}
As far as applying it to your case, there are a few issues. Your first condition is invalid. I believe it will always return true as you never execute the query. I'm also assuming since you are matching an email that there will only be one result. So lets use the query builder method first() to save a step as this will return a single entry instead of an array.
$maintenance = Maintenance::where('email', '=', $email)->first();
if ($maintenance) {
// do stuff
}
Then you have a few more conditions that have similar issues, but more importantly, they are re-querying so you are losing the restrictions in your collection each time.
Instead:
$maintenance = Maintenance::where('email', '=', $email)->first();
if ($maintenance) {
if ($maintenance->maintenance_status === 'PAID') {
// do something
}
}
Finally, to use the value from the database:
if ($maintenance->maintenance_status === 'PAID') {
$date = Carbon\Carbon::parse($maintenance->to_date)->addMonths(6);
$maintenance>to_date = $date->toDatestring();
$maintenance->save();
}