Interview Guides
This question tests whether you understand how join choice changes row retention when data is incomplete. In vehicle operations data, it is common for some VINs to exist in a production or inventory table before a matching delivery record appears.
You are given a table of Lucid vehicle VINs and a table of customer delivery records. Explain the difference between an INNER JOIN and a LEFT JOIN when some VINs do not have corresponding delivery records. Describe which rows each join returns, how NULL values appear in the result, and when you would use each join in analysis.
A strong answer should define both join types clearly, use the VIN-to-delivery scenario directly, and mention how you would identify undelivered vehicles versus delivered-only vehicles. You do not need to discuss advanced optimization or execution plans.
