Aggregates
An aggregate is a set of functions that returns information about a set of query results.
For example, the built-in SUM aggregate adds the values returned from a query and returns the result. An aggregate is invoked in SQL as a single function, but it is implemented as one or more support functions.
You can define two types of aggregates:
- Built-in aggregates whose support functions are overloaded to work with extended data types
- New, user-defined aggregates that implement user-defined routines.
The built-in aggregates are AVG, COUNT, MAX, MIN, SUM, RANGE, STDEV, and VARIANCE. The COUNT aggregate is defined for all data types. For more information about these aggregates, see the HCL Informix® Guide to SQL: Syntax.
For more information about defining aggregates, see the HCL Informix DataBlade Developers Kit User's Guide.