I need a formula for a nested function

[Ginger124]

Hi, can someone help me out with a formula for a nested function.  Here's what I'm trying to do -in column P if the value in column O = 1 then insert a dropdown lists (the list exists as a table on another sheet), if the value in column O does not = 1 then leave column P blank.

Any advice would be super appreciated, I just can't figure out how to do it.

Thanks,

Ginger

[#2]

@Ginger124 I'm quite certain that you can not add data validation (i.e. a dropdown) based on a condition and not have it at all if that condition is not met.

The attached example contains a list for a dropdown (A2:A7). And then D1 has Data Validation that checks if C1 = 1. If so, it returns the list from column A, if not, it returns an empty list. The formula used is

=IF($C$1=1,$A$2:$A$7,"")

So, cell D1 will always show the dropdown button, but if the value in C1 is not equal to 1, nothing can be selected.