=IF(ISBLANK(A1)," ",IF(A1=B1," ",B1))
如图
连接符在这里是不行的你可以在C1中输入公式=IF(AND(A1<>B1,A1<>""),B1)
=if(and(a1<>b1,a1<>""),"",b1)
这样也可以=if(a1<>b1,if(a1<>"",b1,""),"")
=IF(AND(A1<>B1,A1<>""),B1,"")