Interview Guides
Joining datasets is a core part of marketing analytics because campaign, account, and engagement data often live in separate tables. In tools such as Veeva CRM and Veeva Nitro, the join type you choose directly affects row counts, missing values, and the business meaning of the result.
Explain how you would perform a join on two datasets in SQL, and how you would decide which join type to use. You should describe the difference between INNER JOIN and LEFT JOIN, what happens to unmatched rows, and how NULL values appear in the result. Use a simple example such as joining campaign membership data to account records or email engagement data to campaign sends.
The interviewer is looking for a practical explanation rather than a full data modeling discussion. A strong answer should show that you understand join logic, can explain why a specific join type fits the question being asked, and can call out common mistakes such as filtering away unmatched rows after a LEFT JOIN.
