Stumbling Out of the Gate

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

Domain

SQL

Difficulty

medium

Seniority

L4

Problem

Every model version goes through a series of training runs. We want to know how often a version stumbles right out of the gate. For each model version (a unique combination of mdl_name and version), find its very first training run, ordered by train_at. Of those first runs, what percentage ended with a status of 'failed' (status casing is inconsistent in the data)? Only count runs that actually recorded an accuracy score, since a null accuracy means the run never produced a usable metric and should not be considered a real first run. Return a single percentage.

Summary

Some model versions never recover from a bad opening run.

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