Data Validation

[Louise]

Hi all

Using the following formula in data validation will avoid the user entering
duplicate entries, however, I don't understand what the A1 is for.... can
anybody explain to me?

Thank you.

=countif($1:$65536,A1)<2

 

[Gary''s Student]

It just says that whatever is entered in A1 cannot appear in the area more
than one time.

 

[Louise]

but by highlighting the whole worksheet to begin with, the rule has been
applied to every cell any way, not just A1.

Does that make sense??

Thanks, Louise.

 

[Gary''s Student]

You can apply the validation to only a single cell, but reference other cells
in the sheet.