Determine Effective Savings Rate by Service

Postgres SQL, as run

select case when publisher_name is not null and publisher_name is distinct from invoice_issuer_name then publisher_name else provider_name end as service_provider_name,
       service_name as service_name,
       sum(contracted_cost) as contracted_cost,
       sum(effective_cost) as effective_cost,
       (sum(contracted_cost) - sum(effective_cost)) / nullif(sum(contracted_cost), 0) as effective_discount_ratio
from focus.cost_and_usage
where charge_period_start >= $1::timestamptz
  and charge_period_end < $2::timestamptz
group by service_provider_name, service_name
having abs(sum(contracted_cost)) >= 0.01
order by contracted_cost desc nulls last, service_provider_name, service_name
limit 500

Parameters: $1 = period_start, $2 = period_end_before

Original FOCUS SQL

SELECT
  ServiceProviderName,
  ServiceName,
  SUM(ContractedCost) AS ContractedCost,
  SUM(EffectiveCost)  AS EffectiveCost,
  (SUM(ContractedCost) - SUM(EffectiveCost)) / NULLIF(SUM(ContractedCost), 0) AS EffectiveSavingsRate
FROM focus_data_table
WHERE ChargePeriodStart >= ? AND ChargePeriodEnd < ?
GROUP BY ServiceProviderName, ServiceName