Try:

=INDEX(A1:A6,1+MATCH(1,(B1:B6=0)*(B2:B7<0),0))

Array-entered, meaning press ctrl + shift + enter.

HTH
Jason
Atlanta, GA


"LA" wrote:

Hi all,
One of my input workbook consist of 30 worksheets with the 2 colums
referring date and production profile. Below is an example
Column A ColumnB (production profile)
Date1 0
Date2 0
Date3 1
Date4 2
Date5 7
Date6 5
If production profile changes from 0 to <0, then date coresponding to that
production would be "start date".
Now would you help me to set up a formular for a cell to address the start
date of each case.
FYI, I have created a so-called "flag" where startdate has value 1 while
non-startdate has value 0. However, i do not know what step would be.
Tks so much for your help.
LA