DAX function

SUMMARIZE — DAX function reference

Group rows and summarize.

Syntax

dax

SUMMARIZE(<table>, <groupBy_column1> [, <groupBy_column2>, …] [, <name>, <expression>, …])

dax

SUMMARIZE(Sales, Region[Name], "Sales", SUM(Sales[Amount]))

→ A grouped table

Using SUMMARIZE purely for grouping, with no aggregation columns, is the safe, well-supported use case.

dax

SUMMARIZE(Sales, 'Date'[Year], 'Date'[Quarter])

→ Distinct Year/Quarter combinations present in Sales

dax

ADDCOLUMNS(SUMMARIZE(Sales, Product[Category]), "Sales", CALCULATE(SUM(Sales[Amount])))

→ The recommended pattern: group with SUMMARIZE, aggregate with ADDCOLUMNS

Do aggregations with ADDCOLUMNS over SUMMARIZE, or use SUMMARIZECOLUMNS — plain SUMMARIZE aggregation can misbehave.
SUMMARIZE's own extension-column aggregation (the trailing name/expression pairs) can silently return unexpected totals in more complex filter contexts because of how it interacts with the engine's auto-exist behavior — Microsoft's own guidance is to use SUMMARIZE only for grouping and layer aggregations on with ADDCOLUMNS, or use SUMMARIZECOLUMNS instead.
The grouping columns can come from any table connected in the model via a relationship path, not just the table argument itself.

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