To start with, vlookup isn't a formula, it's a function.
Anyway, I don't think there's a way to do this without writing a custom function.
Then the target cell contains something like =myOwnMaxFunction(a1,$c$1:$d$12)
I search a formular similar to vlookup.
I have columns for month / performance / year-performance etc.
In a seperate cell, I enter manually the month I want to gather information from.
So what I want to do is to enter e.g. "July" and have the excel searching in all columns beginning from start (always the same) until the row with the July values.
If I enter "August", I want it to do the same but of course including the row with August numbers etc.
Using below simple example, I want Excel to tell me the maximum value of column "val2" from a fixed start date (here 01.01.2010) until a specified end date (written down in a seperate cell). So if I specify March as end date, result should be 6%, If I specify "April", result should be 7%
date val 1 val 2
01.01.2010 1 6%
01.02.2010 3 2%
01.03.2010 2 5%
01.04.2010 5 7%