To calculate values for a single row using the Expression transformation, you must include the following ports:

You can enter multiple expressions in a single Expression transformation by creating an expression for each output port. For example, you might want to calculate different types of withholding taxes from each employee paycheck, such as local and federal income tax, Social Security and Medicare. Since all of these calculations require the employee salary, the withholding category, and may require the corresponding tax rate, you can create input/output ports for the salary and withholding category and a separate output port for each calculation.