What is dbt - Practice Questions & Exercises

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding dbt's primary function

What is the main purpose of dbt in data workflows?

A It visualizes data through dashboards and reports directly.

B It stores large volumes of raw data in a data lake without transformation.

C It transforms raw data into clean, tested datasets using SQL and version control.

D It collects data from external APIs and loads it into databases.

💡 Hint

Think about what dbt does after data is loaded into a warehouse.

dbt focuses on transforming and testing data inside the warehouse using SQL and version control, not on storage, visualization, or data collection.

🧠 Conceptual

intermediate

dbt's role in the ELT process

In the ELT (Extract, Load, Transform) process, where does dbt fit?

A Extracting data from source systems.

B Loading data into the data warehouse.

C Visualizing data for business users.

D Transforming data inside the data warehouse.

💡 Hint

dbt works after data is already loaded into the warehouse.

dbt is designed to transform data inside the warehouse after extraction and loading are complete.

❓ data_output

advanced

dbt model output structure

Given a dbt model that selects customer_id and total_sales from a raw sales table, what will be the structure of the resulting table after running dbt?

dbt

select customer_id, sum(sales_amount) as total_sales from raw_sales group by customer_id

A A table with raw sales data including all columns from raw_sales.

B A table with columns: customer_id, total_sales aggregated by customer.

C A table with only sales_amount column without aggregation.

D An error because aggregation functions are not allowed in dbt models.

💡 Hint

dbt models create tables or views based on the SQL query you write.

The model runs the SQL query and creates a table or view with the selected columns and aggregation as specified.

🔧 Debug

advanced

Identifying dbt model error

What error will occur when running this dbt model SQL?

select customer_id, total_sales from raw_sales group by customer_id

A Error: 'total_sales' is not aggregated or grouped.

B No error, query runs successfully.

C Error: 'customer_id' must be aggregated.

D Error: 'raw_sales' table does not exist.

💡 Hint

Check if all selected columns are either grouped or aggregated.

Since total_sales is selected but not aggregated or grouped, SQL will raise an error.

🚀 Application

expert

dbt testing output interpretation

After running dbt tests on a model, you see this output:

PASS test_not_null_customer_id (1 passed)

FAIL test_unique_order_id (2 failed)

What does this mean?

A All customer_id values are present, but order_id has duplicates in 2 rows.

B customer_id has nulls, and order_id is unique.

C Both customer_id and order_id columns have no issues.

D Tests did not run correctly due to syntax errors.

💡 Hint

Look at what PASS and FAIL indicate for each test.

PASS means the test succeeded (no nulls in customer_id). FAIL means duplicates found in order_id for 2 rows.