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 on these aggregates, see the IBM Informix: Guide to SQL Syntax.

For more information on defining aggregates, see the IBM Informix: DataBlade Developer's Kit User's Guide.