The Designer allows aggregate expressions only in the Aggregator transformation. An aggregate expression can include conditional clauses and nonaggregate functions. The expression can also include one aggregate function within another aggregate function, such as:

The result of an aggregate expression varies based on the group by ports in the transformation. For example, when the Integration Service calculates the following aggregate expression with no group by ports defined, it finds the total quantity of items sold:

However, if you use the same expression, and you group by the ITEM port, the Integration Service returns the total quantity of items sold, by item.

You can create an aggregate expression in any output port and use multiple aggregate ports in a transformation.