Your question is SQL Join Types for Customer Data. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Joins are fundamental in SQL because most real datasets are split across related tables. Interviewers often ask this question to test whether you understand both result shape and business implications.
Explain the main types of SQL joins: INNER JOIN, LEFT OUTER JOIN, RIGHT OUTER JOIN, FULL OUTER JOIN, CROSS JOIN, and optionally SELF JOIN as a pattern. For each, describe what rows are returned and how unmatched records are handled.
Then give a practical use case for a LEFT OUTER JOIN. Your answer should explain why LEFT OUTER JOIN is the correct choice instead of INNER JOIN, and what kind of business question it helps answer.
The interviewer expects a clear conceptual explanation, not a long theory lecture. Focus on row-matching behavior, NULL handling, and one realistic example such as customers without orders, employees without managers, or products with no sales.