An expression defined for a view. The expression contains an arithmetic formula used for aggregation when querying against the view. Each metric must contain at least one aggregation function (for example, "SUM(x)" or "AVG(y)").
For example, a view that includes the attribute "Sales" may also contain a metric "Total Sales", which is the total of the values of the "Sales" attribute.
Views can have any number of metrics.
See also view.