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XML Data Handling in SQL
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XML Data Handling in SQL

MediumSQL · PostgreSQL

Problem

Tell me about how you handle XML data in your data analysis work using SQL or related tooling.

For this exercise, work with the XML payloads stored in Boeing maintenance event records. Write a SQL query that extracts the event type, tail number, and event timestamp from the XML, keeps only rows with all three values present, and returns the latest valid record for each source system.

Output

  1. One row per source_system
  2. Columns: source_system, event_type, tail_number, event_ts
  3. Keep only rows where all extracted values are present and event_ts is not null
  4. If multiple valid rows exist for a source system, return the most recent event_ts
  5. Sort by source_system ascending

Schema

maintenance_event_records
ColumnTypeDescription
record_idPKINTUnique record identifier
source_systemVARCHAR(50)System that produced the XML record
ingested_atTIMESTAMPWhen the record was loaded
payload_xmlXMLXML payload containing event details
Tablesmaintenance_event_records
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