Learn how to use functions in a formula.
Formulas without control structures execute each expression in the formula exactly once when the formula is evaluated. The expressions are executed in a sequential fashion, from the first expression in the formula to the last.
Control structures enable you to allow some flexibility. Depending upon which control structure you choose, you can skip over some of the expressions or you can repeatedly evaluate some expressions depending on a condition.
Control structures are the primary means of expressing business logic. Typical report formulas make extensive use of them.