[All skill tests](https://jobicy.com/tests.md) Skill assessment # SQL Window Functions Skills Test Test your knowledge and skills with SQL window functions, a powerful tool for advanced data analysis. This assessment focuses on your ability to apply window functions effectively in analytical queries. [Start the test](#test-start) Share Assessment setup Ready ## Choose the level that matches your current experience. * 01 Basic Available * 02 Intermediate Available * 03 Advanced Available Instant result Review your score after submission 20–30 Questions per assessment 15–45 min Estimated completion time 3 levels Choose your difficulty SQL Basics for Analysts [View category](https://jobicy.com/test-category/sql-basics-for-analysts.md) Start assessment ## Choose your level and begin. Answer without outside help so the result reflects your current knowledge. You will see your score after completing the selected assessment. SQL window functions are essential for analysts seeking to perform complex calculations across sets of rows related to the current query row without collapsing the result set. Mastering window functions enables analysts to calculate running totals, ranks, moving averages, and differences, making data insights richer and more precise. Understanding how to use functions such as ROW_NUMBER(), RANK(), LEAD(), LAG(), and aggregate window functions is critical for intermediate SQL users. These skills allow analysts to solve problems involving ordered data, comparative metrics, and partitioned calculations efficiently and elegantly. Basic Intermediate Advanced This is a demo version of the test. You may attempt up to 3 questions. To take the full test and save your results, please [log in](https://jobicy.com/dashboard-page.md) or [create an account](https://jobicy.com/dashboard-page#tab2.md). This is a demo version of the test. You may attempt up to 3 questions. To take the full test and save your results, please [log in](https://jobicy.com/dashboard-page.md) or [create an account](https://jobicy.com/dashboard-page#tab2.md). This is a demo version of the test. You may attempt up to 3 questions. To take the full test and save your results, please [log in](https://jobicy.com/dashboard-page.md) or [create an account](https://jobicy.com/dashboard-page#tab2.md). Test details ## Know what to expect. Review the instructions, covered skills, example question themes, and intended audience before beginning. 01 ### Instructions and covered skills Complete the test without distractions and avoid seeking external help or references. Focus on understanding each question carefully before selecting your answer. This test is designed to evaluate your genuine skills with SQL window functions. ### Key Areas of Evaluation This test evaluates the candidate's ability to understand and apply SQL window functions effectively within analytical queries. It covers key concepts such as: * Understanding the syntax and purpose of various window functions including ROW_NUMBER(), RANK(), DENSE_RANK(), NTILE(), LAG(), LEAD(), FIRST_VALUE(), and LAST_VALUE(). * Using the OVER() clause with PARTITION BY and ORDER BY to segment and order data correctly. * Working with window frames to specify the range of rows for aggregate calculations such as running totals and moving averages. * Distinguishing between ranking functions and aggregate window functions and knowing when to apply each. * Interpreting query results involving nulls, offsets, and default frame behaviors. ### Recommended Preparation To prepare effectively for this test, candidates should: * Review SQL window function documentation and practice writing queries using different window functions. * Understand the differences between ranking, offset, and aggregate window functions. * Practice solving analytical problems such as calculating running totals, moving averages, and row rankings across partitions. * Experiment with window frame clauses like ROWS BETWEEN and RANGE BETWEEN to grasp their implications. * Test queries on sample datasets to observe outputs and understand edge cases such as ties, null handling, and partition boundaries. 02 ### Examples of questions – Which window function assigns a unique sequential integer to rows within a partition? – How does the RANK() function differ from DENSE_RANK() in SQL? – What does the LAG() function do when no offset value is provided? – Which clause defines the partitioning of the data in a window function? – What is the default frame for ROWS BETWEEN in aggregate window functions if not specified? – How do you calculate a moving average using window functions? – What effect does ORDER BY have inside the OVER() clause? – When would you use the LEAD() function instead of LAG()? – How can you reset row numbering for each group in a query? – What happens if you omit the PARTITION BY clause in a window function? 03 ### Who this test is best for This skills test is ideal for data analysts, business intelligence professionals, and data engineers seeking to validate their expertise in advanced SQL querying techniques. Candidates with some foundational SQL knowledge who want to demonstrate their intermediate proficiency with window functions will benefit most from this assessment. ## Share the assessment or try another skill. Send this test to a colleague or friend, or return to the assessment library to explore another professional area. Share this test [Browse all tests](https://jobicy.com/tests.md)