Context

Analysts often use Excel's VLOOKUP to pull columns from one table into another based on a shared key. In SQL, the equivalent idea is combining related tables with joins.

Core Question

Explain how you would translate an Excel VLOOKUP workflow into SQL. Your answer should cover:

1. Which SQL operation is most similar to VLOOKUP
2. How matching keys work across two tables
3. When to use INNER JOIN versus LEFT JOIN
4. What happens when there is no match in the lookup table
5. Common issues such as duplicate keys or missing values

Scope Guidance

The interviewer expects a practical explanation, not just a definition. You should describe the SQL pattern clearly, compare it to how VLOOKUP behaves in Excel, and mention the most common edge cases that affect correctness.