The standard sum function is supported, generating SUM (expression). The type of the resulting value depends on the type of the expression being summed. If the expression is any of the integer types, the resulting value is of type integer. If the expression is a float or character type, the resulting value is of type float. A decimal expression results in a value of decimal type with 18 total digits and the same number of fractional digits contained in the decimal expression. When dragging a Sum into a variable, the following tree element is created.
Columns and/or other non-aggregate expressions can be moved over the (empty) branch of the tree.
The option to compute the sum over distinct values only is provided, resulting in the generation of SUM(DISTINCT expression). This option is enabled through the Properties panel. Double-click on Sum, or highlight it and click Properties.