SAP AGGREGATE FUNCTION - Glossary

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aggregate function
Function that determines a value from the values of multiple rows of a column in the result set of an AB_SQL query or a CDS view entity. The calculation is done in the database system. An aggregate function can be used in an aggregate expression, as a window function in a window expression, and in a hierarchy aggregate navigator.

Aggregate functions in AB_SQL

Aggregate functions in ABAP CDS