VLookup

Please attach a sample workbook with your attempted formulae in place so that we can diagnose the issue.

1. Make sure that your sample data are REPRESENTATIVE of your real data. The use of unrepresentative data is very frustrating and can lead to long delays in reaching a solution.

2. Make sure that your desired solution is also shown (mock up the results manually).

3. Make sure that all confidential data is removed or replaced with dummy data first (e.g. names, addresses, E-mails, etc.).

4. Try to avoid using merged cells as they cause lots of problems.

Unfortunately the attachment icon doesn't work at the moment, so to attach an Excel file you have to do the following: just before posting, scroll down to Go Advanced and then scroll down to Manage Attachments. Now follow the instructions at the top of that screen.

Please pay particular attention to point 2 (above): without an idea of your intended outcomes, it is often very difficult to offer appropriate advice.

I think you are over-thinking this!

All you need is:

=VLOOKUP(I2,$B$2:$C$34,2,0)

because the list is in chronological order and VLOOKUP returns the first instance of the client code in the array.

But the earliest date is listed first in the workbook you gave us. What am I not seeing here?

Please provide sample data that reflects the real data.