结果 全是 AAA

=IF(OR(O7>0,O7<=249),"A",
IF(OR(O7>=250,O7<=499),"B",
IF(OR(O7>=500,O7<=749),"C",
IF(OR(O7>=750,O7<=999),"D","不在指定范围"
))
))



结果 全是 AAA