12.19 Aggregate Functions

12.19.1 Aggregate Function Descriptions

12.19.2 GROUP BY Modifiers

12.19.3 MySQL Handling of GROUP BY

12.19.4 Detection of Functional Dependence

Aggregate functions operate on sets of values. They are often used with a GROUP BY clause to group values into subsets. This section describes most aggregate functions. For information about aggregate functions that operate on geometry values, see Section 12.16.12, “Spatial Aggregate Functions”.