data vaildation help

Posted by excel n00b on January 16, 2002 6:45 AM

How can i make it so that a error box comes up when a value have been entered more then once in a coloum ? i.e. in cell A1 i got the heading colur and then below it i enter: red, green , blue etc. and i wanna make a error msg box appear when one of the colour have been enter twice.

any help will be appricated

Posted by Aladin Akyurek on January 16, 2002 8:12 AM

Select the next empty cell in A,say, A2.

Activate Data|Validation.

Choose Custom for Allow.

Enter as Source:

=COUNTIF($A$1:A1,A2)=0

Enter a message on the Error Alert tab, if you so desire.

and copy down this as far as you need (before entering antthing in those cells).

Aladin