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Maintenance-to-Revenue Top 10% Query
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Maintenance-to-Revenue Top 10% Query

MediumSQL · PostgreSQL

Problem

Given a schema of property acquisitions and monthly maintenance costs, write a query to find the top 10% of properties with the highest maintenance-to-revenue ratio.

Use properties with a positive, non-null monthly revenue. Treat properties without maintenance records as having zero maintenance cost.

Output

  1. One row per property in the highest 10% by ratio.
  2. Include property_id, property_name, monthly_revenue, total_maintenance_cost, and maintenance_to_revenue_ratio.
  3. Sort by ratio descending, then property_id ascending to break ties.

Schema

properties
ColumnTypeDescription
property_idPKINTUnique property identifier
property_nameVARCHAR(100)Property display name
property_acquisitions
ColumnTypeDescription
acquisition_idPKINTUnique acquisition record identifier
property_idINTReferences the acquired property
acquisition_dateDATEDate the property was acquired
monthly_revenueNUMERIC(12,2)Expected monthly revenue for the property
monthly_maintenance_costs
ColumnTypeDescription
maintenance_idPKINTUnique maintenance record identifier
property_idINTProperty associated with the maintenance cost
maintenance_monthDATEFirst day of the maintenance month
maintenance_costNUMERIC(12,2)Maintenance cost recorded for the month
Tablespropertiesproperty_acquisitionsmonthly_maintenance_costs
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