sum( )

Refines a WixDataAggregate to contain the sum from each aggregation group.

The sum() method refines a WixDataAggregate to contain the sum of the values from the specified field for each aggregated group or from the whole collection if no group is defined.

When the aggregation is run(), the returned WixDataAggregateResult object contains an item for each group with the following key:value pairs:

• If a value was passed for the optional projectedField, the key is named using that value. Otherwise, the key is named using the following format: "fieldSum", where field is the name of the specified field.
• The value is the sum of the values found in the specified field.

Sums can only be calculated on fields of type Number.