SQL Query Evaluation Specialist

About OpenTrain OpenTrain is the #1 platform for building careers in AI training and data labeling. We help specialists find and manage AI training work, build a unified portfolio, and grow a durable freelance career doing the technical work they already know how to do best. Why AI training matters AI training is the human side of building modern machine intelligence: people create, review, and correct examples so models learn to behave. This work is often 100% remote, flexible, and accessible to technical experts who want recurring contract work shaping how AI systems reason about data. The role You will evaluate AI-generated SQL, database designs, and data-processing logic; identify correctness, performance, and methodological issues; and produce high-quality reference solutions and explanations that help improve model outputs.

• Position: Remote contractor (part-time, 20+ hours/week).
• Pay: $50 USD per hour.
• Work includes rating, comparing, and writing reference answers for AI responses to SQL and database problems.

What you'll do

• Review AI-generated SQL queries, schemas, and ETL/ELT logic for correctness and clarity.
• Analyze query plans, joins, window functions, and aggregation for correctness and performance.
• Identify issues with indexing strategies, concurrency, locking, and schema design.
• Fact-check data-related claims and validate results against expected behavior or sample data.
• Write detailed, step-by-step reference solutions and explanations that show reasoning and trade-offs.
• Rate and compare multiple AI responses for correctness, completeness, and methodological soundness.
• Contribute database engineering expertise to annotation guidelines and training examples.

Requirements

You must meet the technical requirements below to be considered. We will preserve these criteria when reviewing applications.

• Expert-level SQL, including complex joins, window functions, aggregation, and query plan analysis.
• Experience with database performance tuning, indexing strategies, and concurrency/locking issues.
• Hands-on experience with relational data models, schemas, and data warehouse structures.
• Strong ETL or ELT experience and familiarity with cloud or on-prem data platforms.
• Comfort with version control, CI/CD practices, and collaborative database workflows.
• Clear written and spoken English and the ability to explain technical reasoning precisely.
• Bachelor's degree or higher in a related technical field.

Helpful background

• Experience designing star and snowflake schemas.
• Familiarity with migrations, backup/recovery planning, and monitoring.
• Methodical approach to finding subtle data, logic, or query issues.
• Prior experience evaluating AI-generated technical content or participating in AI data training is a strong plus.

Schedule, location, and application details This is an hourly, remote contractor role; you will be paid per hour at the listed rate. The role expects 20+ hours per week and is open to qualified contractors in approved countries (see list below). English is required for written and spoken communication.

• Hourly rate: $50 USD per hour (PAY_PER_HOUR).
• Minimum time commitment: 20+ hours/week.
• Languages: English required.
• Approved countries: BD, BT, BR, KH, DE, IN, ID, MY, NP, PK, SG, LK, TH, PH, US, TL, VN.
• Employment types: Contractor, Part-time.