Measures
Explicit measures are model calculations that are written in DAX and are commonly referred to as simply measures.
Implicit measures are columns that can be summarized by visuals in simplistic ways, like count, sum, minimum, maximum, and so on.
In the Fields pane, a column that’s shown with the sigma symbol ( ∑ ) indicates two facts:
- It’s a numeric column.
- It will summarize column values when it is used in a visual (when added to a field well that supports summarization).
When a measure references one or more measures, it’s known as a compound measure.
Removing this columns results in a decreased semantic model size and shorter data refresh times.
you can create quick measures, not quick columns
similarities between calculated columns and measures, both are: - Calculations that you can add to your semantic model. - Defined by using a DAX formula. - Referenced in DAX formulas by enclosing their names within square brackets.
The areas where calculated columns and measures differ include: - Purpose - Calculated columns extend a table with a new column - measures define how to summarize model data. - Evaluation - Calculated columns are evaluated by using row context at data refresh time - measures are evaluated by using filter context at query time. - Storage - Calculated columns (in Import storage mode tables) store a value for each row in the table - measure never stores values in the model. - Visual use - Calculated columns (like any column) can be used to filter, group, or summarize (as an implicit measure) - measures are designed to summarize.