Where the Rows Go

A easy SQL interview practice problem on DataDriven. Write and execute real sql code with instant grading.

Domain

SQL

Difficulty

easy

Seniority

mid

Problem

Our ingestion pipelines read raw records and write cleaned ones, and each job stamps its own run status, so a run that finished shows up as 'success' in whatever mix of upper and lower case that job happens to use. Across the runs that finished successfully, find the pipelines losing the most records between what they read and what they wrote, biggest losses first.

Summary

Every batch reads more than it writes. Find the pipelines quietly losing the most on the way through.

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