how to make number unique in Excel column?

[Bob]

I am entering a long list of ID numbers. Can I get Excel to reject ID if it
has already been used?

 

[Paul B]

Bob, you can use data validation to keep people from putting duplicate
numbers in a column, select column A, data, validation, custom, formula: =
COUNTIF($A:$A,A1)<2
--
Paul B
Always backup your data before trying something new
Please post any response to the newsgroups so others can benefit from it
Feedback on answers is always appreciated!
Using Excel 2002 & 2003

 

[Bob]

Brilliant, many thanks Paul B. I owe you a drink.

Bob