Try the below. With your data as below try the below formula in cell D2.
Please note that this is an array formula. An array formula can perform
multiple calculations and then return either a single result or multiple
results. Array formulas act on two or more sets of values known as array
arguments. Each array argument must have the same number of rows and columns.
You create array formulas in the same way that you create other formulas,
except you press CTRL+SHIFT+ENTER to enter the formula. If successful in
'Formula Bar' you can notice the curly braces at both ends like "{=<formula}"

=INDEX(B1:B9,MAX(IF(A1:A9=C2,IF(B1:B90,ROW(B1:B9) ))))

Col A Col B Col C Col D
Date Value Query date Result
9/8/2009 0 9/8/2009 =formula
9/8/2009 3
9/8/2009 2
9/8/2009 1
9/9/2009 2
9/9/2009 2
9/9/2009 3

If this post helps click Yes
---------------
Jacob Skaria


"Ana" wrote:

I need some help with a formula
I have 2 colonnes A and B
In colonne A I have dates and in B values , but for some dates the value in
B es 0, so I need a formula that gives the last value in B <0, or the date I
have the last value
anyone knows?
thank you