excel formula - Find each customer's second order date in a list of all orders

Question

I have a list of all orders placed in a time range and I am trying to calculate the difference between each customer's first and second order. I have a list of unique customer IDs on another tab and I already have the first order date for each. I need a way to grab the date of the second order, corresponding to each customer ID.

In the sample data below, the correct output of this formula for customer ID "153950" would be "5/11/17 8:41".

Answer 1

Use AGGREGATE()

=AGGREGATE(15,6,Sheet1!C1:C4/(Sheet1!A1:A4 = 153950),2)

The ,2 is grabbing the second smallest date.