sorgu dogru gibi duruyor
sadece group by yanlis gibi
birde direkt day number i cekebilirsin DOW olmasi lazim

select
  COUNT(*) as count,
  date_trunc('day', orders.createdAt) as day
from orders
WHERE orders.createdAt BETWEEN date_trunc('week', current_date) AND date_trunc('week', current_date) + INTERVAL '6 days'
GROUP BY 2