Data Validation

[lmcd5666]

Simple question..I hope.

Is there a way to prevent duplicate number in a column?

Thanks in advance!

Toan

 

[Andrew Poulsom]

Select your range and choose Data Validation from the menu. Choose Allow custom and use this formula:

=COUNTIF(A$1:A$10,A1)<=1

where A1:A10 is the validation range and A1 is the first cell in your selection.

 

[lmcd5666]

Thank you very much, Andrew.

Toan