SQL Reference Guide

Functions

Functions are a type of FairCom DB SQL expression that return a value based on the argument they are supplied. FairCom DB SQL supports two types of functions:

Aggregate functions calculate a single value for a collection of rows in a result table (if the function is in a statement with a GROUP BY clause, it returns a value for each group in the result table). Aggregate functions are also called set or statistical functions. Aggregate functions cannot be nested.
Scalar functions calculate a value based on another single value. Scalar functions are also called value functions. Scalar functions can be nested.

FairCom DB SQL does not provide a mechanism for calling a scalar function directly from a user-defined function. To use scalar functions, it is necessary to call the function from within a FairCom DB SQL statement. FairCom DB SQL defines the special table SYSCALCTABLE which has only one row for use in situations where all the data is in the inputs.

In This Section