DAX Detective: Power BI Measures and Filter Context

What's inside

1. Level 1: Measures vs Calculated ColumnsFree
   Learn when to use a measure and when to use a calculated column, and why an explicit measure is better than the implicit one Power BI makes when you drag a numeric field into a visual. The lesson also says that this course is independent of Microsoft.
2. Level 2: The Star Schema and RelationshipsFree
   Learn how fact and dimension tables in a star schema are joined by relationships, and how cardinality sets the way filters flow from dimensions to facts.
3. Level 3: Cross-Filter Direction and Bidirectional Traps
   Learn how single and both cross-filter directions decide which way filters travel, and why bidirectional filters give results you did not expect.
4. Level 4: Where Filter Context Comes From
   Learn to name every source of filter context on a visual cell: rows, columns, slicers, cross-highlighting, and visual-level, page-level and report-level filters.
5. Level 5: Row Context and Iterators
   Learn what row context is, how iterators such as SUMX, AVERAGEX and COUNTROWS go through a table one row at a time, and why row context does not filter anything by itself.
6. Level 6: Context Transition
   Learn how calling a measure, or wrapping an expression in CALCULATE, inside a row context turns the current row into a filter context, and how that can change results without warning.
7. Level 7: CALCULATE and Its Filter Arguments
   Learn how CALCULATE changes filter context with its filter arguments, and how a Boolean filter differs from FILTER over a whole table.
8. Level 8: REMOVEFILTERS, ALL and ALLEXCEPT
   Learn to remove filters on purpose with REMOVEFILTERS, ALL and ALLEXCEPT, so a measure ignores some parts of the filter context and keeps others.
9. Level 9: ALLSELECTED and KEEPFILTERS
   Learn how ALLSELECTED respects what the user picked in slicers outside the visual, and how KEEPFILTERS makes a CALCULATE filter intersect with the existing one instead of replacing it.
10. Level 10: Totals That Do Not Add Up
    Learn why a total row calculates the measure again over a wider filter context instead of summing the visible rows, and how to fix such totals on purpose when the business needs a sum.
11. Level 11: DIVIDE, Blanks and Variables
    Learn to write safe ratios with DIVIDE, see how blanks spread through calculations and visuals, and use VAR and RETURN to make measures easier to read, faster and easier to debug.
12. Level 12: Date Tables and Classic Time Intelligence
    Learn to build and mark a continuous date table and write year-to-date, same-period-last-year and DATEADD measures that behave correctly in visuals.
13. Level 13: Calendar-Based Time Intelligence (Preview)
    Learn what the calendar-based (enhanced) time intelligence preview adds, such as defined calendars for fiscal, retail or week-based years and functions like TOTALWTD, and how it compares with the classic functions.
14. Level 14: Percent of Total and Ranking
    Learn to build percent-of-total measures against different totals, and rank items with RANKX while handling ties, blanks and filtered totals.
15. Level 15: Proving a Measure: Matrix, DAX Query View, Performance Analyzer
    Learn a repeatable way to check a measure: compare it against a hand-calculated matrix, query it directly in DAX query view, and time it with Performance Analyzer.
16. Level 16: Copilot Measures, Naming and Documentation
    Learn to ask Copilot in DAX query view (a preview feature) for a measure, check its answer before trusting it, and name, organise and document measures so others can trust them too.
17. Level 17: Final Challenge: The Case of the Wrong Report Exam
    Apply the whole course to a small, broken star-schema report: diagnose wrong totals, slicer surprises and time intelligence errors, fix each one on purpose, and prove every fix.

Access

The first 2 levels are free with a free account. Every level, the podcast edition and the AI tutor come with All Access at £4.99/month or any Creator plan — see pricing.

Start free →