sum
The sum
function adds the set of numbers in the specified
measure, grouped by the chosen dimension or dimensions. For example,
sum(profit amount)
returns the total profit amount grouped by
the (optional) chosen dimension.
Syntax
sum(measure, [groupby level])
Arguments
 measure

The argument must be a measure. Null values are omitted from the results. Literal values don't work. The argument must be a field.
 groupby level

(Optional) Specifies the level to group the aggregation by. The level added can be any dimension or dimensions independent of the dimensions added to the visual.
The argument must be a dimension field. The groupby level must be enclosed in square brackets
[ ]
. For more information, see LACA functions.
Examples
The following example returns the sum of sales.
sum({Sales})
You can also specify at what level to group the computation using one or more dimensions in the view or in your dataset. This is called a LACA function. For more information about LACA functions, see LACA functions. The following example calculates the sum of sales at the Country level, but not across other dimensions (Region and Product) in the visual.
sum(Sales, [Country])