Lets you write common DAX logic like prior year or year-to-date once, as calculation items, and apply it to any explicit measure via SELECTEDMEASURE, so you need far fewer near-duplicate measures. Adding one to a semantic model discourages implicit measures.
Read more: Microsoft Learn
In the Ultra Transcenders books
Each book explains Calculation group in context, with comparison tables and the common traps.
Terms in this definition
- DAX
Short for Data Analysis Expressions, the formula language you write measures, calculated columns and row-level security rules in, within tabular semantic models in Power BI, Excel Power Pivot or Analysis Services.
- LIKE
Compares strings with a pattern that can contain the % and _ wildcards. Because it only understands character patterns, searching big volumes of text this way is much slower than using full-text search.
- PY
Measures such as Sales PY use this tag to mean prior year. With calculation groups, there's no need for a separate prior-year version of every base measure.
- YTD
Year to date: totalling from January 1st (or a fiscal year start) up to now, which DAX handles through TOTALYTD or DATESYTD.
- APPLY
Evaluates a table-valued expression for every row on its left, inside
FROM. Think ofOUTER APPLYas a left outer join andCROSS APPLYas an inner join. - Measure
A figure like total revenue, worked out by aggregating fact table data wherever dimensions intersect within a semantic model.
- SELECTEDMEASURE
Stands in for whichever measure happens to be evaluated, inside calculation items or dynamic format strings. That lets one calculation group add, say, YTD behaviour to all measures at once.
- Semantic model
Sometimes called an OLAP model, this Power BI and Fabric layer defines the measures, hierarchies, tables and relationships that reports and dashboards query; star schema design is the usual pattern.