ETL Concepts: Extract, Transform, Load processes, data warehousing, and data modeling. SQL: Strong knowledge of SQL queries, data manipulation, and performance optimization. ETL Tools: Familiarity with commonly used ETL tools (e.g., Informatica, Talend, SSIS). Problem-Solving: Ability to analyze problems, break them down into steps, and propose effective solutions. Communication: Clear and concise communication skills, both verbal and written. Technical Questions: Be prepared to answer questions about specific ETL techniques, data quality issues, and performance optimization.