Create a drop down list with customers from a database with many entries of same customer

Hi

I have a database containing employee timesheet information and I need to be able accurately to extract expended hours monthly by customer name. There are multiple entries of each customer and many are not established customers. What formula can I use to show just one entry of each customer name from the database which I can create a drop-down list for data validation? Thanks for your assistance

Hi

I tried to but it wouldn't upload. Where is the attachment button?

There is no facility visible to attach a file!

You can easily get a non-duplicated list of Customer Names if you use a pivot table. It won't matter if you include any other data in the Pivot table, you only need the names. Then COPY - PASTE SPECIAL VALUES the Names onto a new sheet. Those names become the basis for your drop down list.