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The most important distinction in DAX is between a calculated column and a measure. A calculated column is evaluated row by row at refresh time, stored inside the model, and operat...
CALCULATE is the single most important function in DAX. It evaluates an expression under a modified filter context, replacing or adding filters as specified in its arguments. A pat...
Time intelligence in DAX requires a properly configured date table. Mark a table as the date table in the Modeling tab, ensure it contains a continuous, unique list of dates with n...
Iterator functions evaluate an expression for each row of a table and then aggregate the results. SUMX(Sales, Sales[Quantity] * Sales[UnitPrice]) multiplies quantity by unit price...
Calculation groups let you define reusable transformation patterns that apply to any measure on a visual. For example, a single calculation group can define YTD, prior year, and mo...
Best practices for measure authoring begin with avoiding implicit measures. Power BI auto-creates aggregations for numeric columns, which leads to inconsistent behavior, missing fo...