From AgileApps Support Wiki
About the Formula Functions
Formula functions are logical and programmatic functions that can be included anywhere that a Formula Expression is defined.
The following conventions are used in these functions:
Element Description 'string' Strings must be enclosed with single quotes 'dString' Date strings must be enclosed with single quotes int An integer,for example, a number representing the number of days (or months or years) value An argument in date- and date/time-related Formula Functions, which defines a unit of time [ ,optional] Optional values are shown in brackets, as [ ,option1, option2]
See Date for details about these Day, Date and Time-related formula functions:
See Logical for details about functions resulting in TRUE/FALSE (YES/NO, 1/0):
See Math for details about mathematical functions:
See Text for details about text-related formula functions:
The Aggregate Functions are not available in every context, because of their potential impact on performance. They let you select a collection of records in an arbitrary object and perform a summary calculation on those records.