DBT Study Guide 2026
Everything you need to pass the DBT exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 DBT Exam Format at a Glance
📚 DBT Topics to Study (22)
✍️ Sample DBT Questions & Answers
1. What does `{{ dbt_utils.union_relations(relations=[ref('a'), ref('b')]) }}` do?
`dbt_utils.union_relations()` generates a UNION ALL query across a list of relations, aligning columns by name and filling missing ones with NULLs.
2. Which command is used to validate the structure and syntax of a dbt project?
The `dbt debug` command is used to validate the structure and syntax of a dbt project, as well as test the connection to your data warehouse. It provides detailed output about your profile configuration, project setup, and any potential issues that might prevent dbt from running successfully. This helps in troubleshooting and ensuring your environment is correctly configured.
3. What does `{# This is a comment #}` do in a dbt SQL file?
Jinja comments (`{# ... #}`) are stripped entirely during compilation and do not appear in the generated SQL sent to the warehouse.
4. What dbt Cloud feature lets a CI job use prod table results for unmodified models instead of rebuilding them?
Deferral (`--defer`) tells dbt to use a different environment's tables for refs that are not being rebuilt in the current run.
5. Why is using CTEs (Common Table Expressions) beneficial for query performance and maintenance?
Common Table Expressions (CTEs) improve query performance and maintenance by breaking down complex SQL queries into smaller, more readable, and manageable logical blocks. While CTEs themselves don't always directly optimize execution plans, they allow the database optimizer to potentially reuse intermediate results and can make queries easier to understand and debug. This modularity often leads to better-structured and more efficient queries.
6. Which version control system is most commonly used with dbt projects?
Git is the most widely adopted version control system for software development, and it is also the standard for dbt projects. It allows teams to track changes to code, collaborate effectively, and manage different versions of their dbt models, tests, and configurations. Its distributed nature and robust branching/merging capabilities make it ideal for managing complex data transformation workflows.