Hi
the formula working in the formula screen but the cell always 0

"Biff" wrote:

Hi!

Try this:

Column A = product (A, B, C)
Column C = dates produced

This is an array formula. It MUST be entered using the key combination of
CTRL,SHIFT,ENTER:

This is for product "A":

=MAX(IF(A1:A20="A",C1:C20))-MIN(IF(A1:A20="A",C1:C20))

Adjust ranges to suit.

Biff

"adam" wrote in message
...
every day we record the product name, quantity and the date, how to make
lookup or vlookup (or any other function) find the first date and the last
date for specific product to calculate for how many days this product
produced
example; we have products a,b and c we record the quantity produced every
day for 30 days (also record the date) the columns ( product / qty / date)
if the product b records only in days 5,6,8,15 and 20 of the month i need
formula to know the the first date is 5 and the last date is 20 the result
should be 15 days
thanks