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Average Delivery Time by Driver (SQL)

EasySQL · PostgreSQL00:00
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Your question is Average Delivery Time by Driver (SQL). Start with the requirements and the two tables on the right.

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Problem

Porter Operations needs to monitor how long active drivers take to complete deliveries. Write a PostgreSQL query that calculates each active driver's average completed delivery time.

Requirements

  1. Return every active driver, including drivers with no eligible completed deliveries.
  2. Include only deliveries with status completed and both pickup and delivery timestamps present.
  3. Calculate the average delivery time in minutes, rounded to two decimal places. Return NULL when a driver has no eligible deliveries.
  4. Sort by average delivery time from highest to lowest, placing drivers with no average last.

Schema

drivers
ColumnTypeDescription
driver_idPKINTEGERUnique driver identifier
driver_nameVARCHAR(100)Driver's name
driver_statusVARCHAR(20)Current driver status
deliveries
ColumnTypeDescription
delivery_idPKINTEGERUnique delivery identifier
driver_idINTEGERAssigned driver identifier
delivery_statusVARCHAR(20)Current delivery status
picked_up_atTIMESTAMPTZPickup timestamp
delivered_atTIMESTAMPTZDelivery completion timestamp
Tablesdriversdeliveries
Your solutionPostgreSQL
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