Display an alert if an entered value already exists
Posted by sid on September 12, 2001 5:14 PM
I have a list of numbers on a sheet formed from 3 columns eg d1 = a1&b1&c1
On another sheet I want to input a similar arrangent but on completion of the 3rd cell, to check this total number against the d column list and if it already exists, display an alert and empty the 3rd cell.
I have been playing about with vlookup in a separate column and trying to display a message based on a true/false value in that cell.
Any help on the best way to do this would be greatly appreciated.