Below are definitions of the various field types, and aggregates, available in custom reports.
Field Types
Boolean
A field that can be one of two values (Yes or No).
Varchar
A variable character field with an indeterminate length.
Numeric
A numeric field hold numbers to be calculated.
Integer
An integer field uses whole numbers (no fractions or decimals).
Date
The date associated with a piece of data (YYYY-MM-DD).
Array
A collection of variables.
Aggregates
Count
The number of rows in a column.
Dcount
The distinct number of instances of data in a column.
Sum
The sum on an amount.
Avg
The average of an amount
Min
The minimum amount in a field
Max
The maximum amount in a field.