同訂單號 不同庫存 ID個數 (14823)

F2{=COUNT(0/(MATCH(1&C$2:C$19,(B$2:B$19=E2)*1&C$2:C$19,)=ROW($1:$18)))

另解 {=SUM(IFERROR((B$2:B$19=E2)/COUNTIFS(B:B,B$2:B$19,C:C,C$2:C$19),))

另解=SUMPRODUCT((B$2:B$19=E2)/TEXT(COUNTIFS(B:B,B$2:B$19,C:C,C$2:C$19),"0;;1"))