# What function do I use to do a lookup in a descending array?

I have a 4-column array.  Column A contains dates in ascending order.  Column D contains numeric values in descending order.  The values in Column D descend until one row contains 0 and all subsequent rows are empty.

I need a formula to return the date from column A that is in the same row as the value 0 in column D.

I have tried using VLookup and other functions, but they all seem to require that the value I am looking for must be in column A with the value returned from some column to the right.

To accommodate that requirement, I tried using a "ghost" column to the right of column D which has the same values as my column A.  But the second requirement is that the array has lookup values in ascending order.  Mine are in descending order.

What function (or rather, what formula) should I use?
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Excel VBA DeveloperCommented:
When you're looking for data that is to the left of your reference data, you use the combination of the INDEX and MATCH functions to get your result.

In your case, the formula to return the date in column A whose associated value in column D is zero would be:
=INDEX(A:A,MATCH(0,D:D,0))

The MATCH function looks for the first occurance of zero (0) in column D and returns position; essentially, the row number.  The INDEX function is looking in column A and returns the item in the row number found in the MATCH function.

Regards,
-Glenn
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Author Commented:
Thanks!  I was sure it was simple, but not obvious to me!
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Excel VBA DeveloperCommented:
Here's some references that may help:

MATCH function
INDEX function
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