Forecast amortized costs month over month based on historical trends

Postgres SQL, as run

select date_trunc('month', billing_period_start at time zone 'UTC') as billing_month,
       provider_name as provider_name,
       service_category as service_category,
       service_name as service_name,
       charge_category as charge_category,
       sum(effective_cost) as total_effective_cost
from focus.cost_and_usage
where billing_period_start >= $1::timestamptz
  and billing_period_end < $2::timestamptz
group by 1, provider_name, service_category, service_name, charge_category
order by billing_month, total_effective_cost desc nulls last, provider_name, service_name
limit 500

Parameters: $1 = billing_period_start, $2 = billing_period_end

Original FOCUS SQL

SELECT
  MONTH(BillingPeriodStart),
  ProviderName,
  ServiceCategory,
  ServiceName,
  ChargeCategory,
  SUM(EffectiveCost) AS TotalEffectiveCost
FROM focus_data_table
WHERE BillingPeriodStart >= ?  AND BillingPeriodEnd < ?
GROUP BY
  MONTH(BillingPeriodStart),
  ProviderName,
  ServiceCategory,
  ServiceName,
  ChargeCategory