刪後面逗點 (9277)

C2=LEFT(B2,LOOKUP(1,-MID(B2,ROW($1:99),1),ROW($1:99)))

另解=LEFT(B2,LEN(B2)-SUMPRODUCT(N(RIGHT(B2,ROW($1:$9))=REPT(",",ROW($1:$9)))))

另解=LEFT(B2,FIND(REPT(",",99),B2&REPT(",",99))-1)