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SQL for Delivery Performance
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SQL for Delivery Performance

MediumSQL · PostgreSQL

Problem

Write a SQL query to calculate weekly delivery success rate, average turnaround time, and failure counts by site from operational tables for Zipline.

Use requested_at to determine the delivery week. Treat delivered as successful and calculate turnaround time only for successful deliveries. Include each site-week with at least one delivery attempt.

Output

  1. One row per site and week, with site_name, week_start, success_rate, average_turnaround_minutes, and failure_count.
  2. Express success_rate as a percentage rounded to two decimals and turnaround time in minutes rounded to two decimals.
  3. Sort by week_start ascending, then site_name ascending.

Schema

sites
ColumnTypeDescription
site_idPKINTUnique identifier for a Zipline operating site
site_nameVARCHAR(100)Human-readable operating site name
deliveries
ColumnTypeDescription
delivery_idPKINTUnique identifier for a delivery attempt
site_idINTOperating site associated with the delivery attempt
requested_atTIMESTAMPTimestamp when the delivery was requested
delivered_atTIMESTAMPTimestamp when the delivery was completed
statusVARCHAR(20)Delivery outcome, either delivered or failed
failure_reasonVARCHAR(100)Reason recorded when a delivery fails
Tablessitesdeliveries
Interviewer

Your question is SQL for Delivery Performance. Start with the requirements and the two tables in the Question tab.

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