Cell Validation

[markster]

Hello

I need to get someone to enter data in a spreadsheet. They will be entering in column a. I need to fix it so the person entering the data cannot enter duplicate numbers so saying 1234 appears in cell a1, if they try to put the same number in in say a100 it won't let them.

Is this possible? and if so how?

Thanks

 

[Richard Schollar]

1. Select A1:A1000 (or whatever range is appropriate)
2. Go Data>Validation>Allow: Custom and use a formula of:

=COUNTIF($A:$A,$A1)<2

and hit OK.

 

[stanleydgromjr]

markster,

Highlite the range, say A1:A1000
Data, Validation, Settings tab, "Allow:" box, pick "Custom", enter into the "Formula:" box, the following formula:
=COUNTIF($A$1:$A$1000,A1)=1

Then enter into two cells:
1234


Have a great day,
Stan

 

[markster]

thanks guys.
M