Debug a Hive query
Company: TikTok
Role: Software Engineer
Category: Data Manipulation (SQL/Python)
Difficulty: Medium
Interview Round: Technical Screen
You are given a prewritten Hive SQL query that produces incorrect results. Describe how you would debug it: identify logical errors (e.g., join conditions, aggregations, window functions, filters, partition predicates), fix the query, and validate correctness with test cases and data checks. Explain any performance optimizations you would make and why.
Quick Answer: This question evaluates a candidate's ability to debug and validate Hive SQL queries, assessing competencies in identifying logical errors (incorrect join conditions, aggregation and window function misuse, filters and partition predicates), validating results with test cases, and reasoning about performance optimizations.