Level 75
A groupby is like:
$quy = Powner::query()->leftJoin('dc_pets', 'dc_powners.ownerid', '=', 'dc_pets.ownerid')
->select('dc_powners.ownerid', 'dc_powners.oname')
->selectRaw('count(dc_pets.petid) as countOfPets')
->groupby('dc_powners.ownerid')
->orderby('dc_powners.oname')
->get();
Results basically give:
ownerid, oname, countOfPets
Like:
5|Bob|3
4|Greg|9
2|Rob|1
Just adapt to what you need and use sum instead of count. A good tutorial on sum:
https://www.mysqltutorial.org/mysql-sum/ has many examples.