when the control break of the aggregate is the same as a longest control break of the order list of control breaks, and the aggregate of the expression is of the form AGG(C0), replacing the expression AGG(C0) OVER (PARTITION BY C1, C2, . . . , Cn) with an expression of the form AGG(C0), where each C is a column and where n is the number of columns in the longest control break.