· Use conditional clauses in the aggregate expression to reduce the number of rows used in the aggregation. The conditional clause can be any clause that evaluates to TRUE or FALSE. For example, use the following expression to calculate the total commissions of employees who exceeded their quarterly quota: SUM ( COMMISSION, COMMISSION > .
However, if you take the system process version of this same activity, you will find that all emissions from mining up to making steel are already in the process record. You will also find that there are no links to other processes, only substance and emissions. The system process is experienced as a black box – you cannot see easily which steps from previous processes are .