BigData / Tableau Interview Questions
What is a context filter, and why would you use one?
A context filter is a filter you promote to run before all other (non-context) filters on the same worksheet, creating a temporary, filtered "context" that every other filter and calculation then operates within.
- Performance: if a worksheet has a filter that dramatically shrinks the data (e.g. Region = "West"), making it a context filter means Tableau only has to evaluate subsequent filters against that smaller subset, instead of the full dataset each time.
- Correctness for dependent filters: a "Top 10 Customers by Sales" filter needs to know the correct universe of customers to rank — if you also want that ranking limited to one region, the region filter must run first, which requires making it a context filter.
Right-click the [Region] filter pill -> "Add to Context"
Context filters aren't free, though: changing a context filter forces Tableau to rebuild the temporary table behind the scenes, which has its own cost, so they're best used for filters that are large, static, and shared across many dependent calculations, not ones that change frequently.
Invest now in Acorns!!! 🚀
Join Acorns and get your $5 bonus!
Acorns is a micro-investing app that automatically invests your "spare change" from daily purchases into diversified, expert-built portfolios of ETFs. It is designed for beginners, allowing you to start investing with as little as $5. The service automates saving and investing. Disclosure: I may receive a referral bonus.
Invest now!!! Get Free equity stock (US, UK only)!
Use Robinhood app to invest in stocks. It is safe and secure. Use the Referral link to claim your free stock when you sign up!.
The Robinhood app makes it easy to trade stocks, crypto and more.
Webull! Receive free stock by signing up using the link: Webull signup.
More Related questions...
