// ============================================================================
// Query: Cost by Region (Custom Date Range)
// Description:
//   Returns total effective cost by region for a custom date range.
//   Useful for regional cost breakdowns and optimization.
// Author: FinOps Toolkit Team
// Parameters:
//   startDate: Start date for the reporting period (e.g., startofmonth(ago(30d)))
//   endDate: End date for the reporting period (e.g., startofmonth(now()))
// Output:
//   Each row represents a region with its total effective cost for the period.
// Usage:
//   Use this query to analyze and optimize regional Azure spend.
// Last Tested: 2025-05-17
// =========================================================================

let startDate = startofmonth(ago(30d)); // Set default as needed
let endDate = startofmonth(now());
Costs()
| where ChargePeriodStart >= startDate and ChargePeriodStart < endDate
| summarize EffectiveCost = sum(EffectiveCost) by RegionName
| order by EffectiveCost desc