By default, Power BI assigns a default summarization to numeric columns, and this default summarization is usually a sum operation. Columns that have been assigned a default summarization are denoted by Power BI with a Sigma symbol (∑). DateKey, Day Number of Week, Day Number of Month, Day Number of Year, and Week Number of Year have all been assigned a default summarization by Power BI in the following screenshot:
Figure 23-Default assigned columns for sumarization
This automatic assignment of default summarizations can cause a lot of confusion to report developers in Power BI. Columns that have a default summarization ...
