Tableau Desktop Foundations (TDS-C01) · 23% practice allocation
5 free sample questions from the Connecting to and Preparing Data domain, with answers and explanations. The full TDS-C01 bank has 51 questions across 4 domains. Questions are scenario-based and written from the official Tableau exam guide.
Which join type returns only the rows that have matching values in BOTH tables?
An inner join returns only rows with matches in both tables. A left join (B) keeps all left-table rows plus matches, a full outer join (C) keeps all rows from both, and a union (D) stacks rows from tables (not a join at all).
A user wants the fastest possible performance and the ability to work offline with a large dataset that doesn't need up-to-the-second freshness. Which connection type should they choose?
An extract gives fast, offline-capable performance from a saved snapshot — ideal when real-time freshness isn't required. A live connection (B, D) queries the source each time and needs the source available, and option C is false.
A user needs to combine two tables that have the SAME columns (e.g., January sales and February sales) by stacking their rows into one table. What should they use?
A union appends rows from tables with the same structure (stacking Jan and Feb sales into one table). A join (B) combines columns by matching keys, a calculated field (C) derives new values, and a filter (D) limits rows shown.
A user wants to reuse a cleaned, well-labeled connection across multiple workbooks. What should they create?
Saving/publishing a data source lets multiple workbooks reuse the same connection, field naming, and preparation. A story (B) and dashboard action (C) are presentation/interaction features, and a table calculation (D) computes values within a view.
A wide table has monthly columns (Jan, Feb, Mar, …) that should be a single 'Month' dimension and a single 'Value' measure for analysis. Which data-prep action reshapes it?
Pivoting turns the wide month columns into two fields — a 'Month' dimension and a 'Value' measure — the tidy shape Tableau prefers. Split (C) divides a single field's text, union (D) stacks tables, and hiding (B) just removes fields from view.
The free TDS-C01 practice test mixes about 20 questions weighted like the exam. The full 51-question bank adds instant grading, flashcards and a timed mock exam.