Suppose that I have a sheet with a list of staff as follows:

A B C D
1 Name Age Work.Yrs Staff Level
2 Mr.A 30 3 ?
3 Ms.B 45 5 ?
4 Ms.C 22 1 ?

And another table below this list:

6 Age Work.Yrs Staff Level
7 <30 <2 A
8 =30 =2 B

How to make cells in column D automatically refer to the reference table? I
have tried a lot of times with VLOOKUP but failed, and I think this function
is not suitable to range criteria (<,). If there are a lot of criteria here,
i.e. 10, function IF also fails.

How do I deal with this situation? Is there anybody who can help me?

Thanks alot.