Simple aggregate functions, such as AVG, COUNT, MAX, MIN, and SUM summarize data over a group of rows from the database. The groups are formed using the GROUP BY clause of the SELECT statement. These aggregates are allowed only in the select list and in the HAVING and ORDER BY clauses of a SELECT statement.
With the exception of Grouping() functions, both the
simple and unary aggregates can be used in a windowing function
that incorporates a <window clause> in a SQL query specification
(a window) that conceptually creates a moving
window over a result set as it is processed. See “Windowing”.
See “Aggregate functions,” Chapter 4, “SQL Functions,” in Reference: Building Blocks, Tables, and Procedures.
