I am trying to set up a spreadsheet with invoice numbers. When I enter a new number excel will look at the old numbers to see if there is a match, if so it will flag it and let me know. If not excel will do nothing and add the new number.
assuming your invoice numbers are in column A, try conditional formatting where it colours any duplicates in red :
Highlight column A
change "cell value is" to "formula is"
enter the formula :=COUNTIF($A$1:$A$1000,A1)>1
click on Ferrari red
this'll highlight in red any invoice number duplicates...... ie drawing your attention to them immediately : it's manual rather than automated, but it's what I tend you use for manual lists that require no duplicates
(obviously, adjust "A" to be your column and "1000" to be your expected column depth, bearing in mind future entries)
Hope this helps,
[Excel '97; Windows ME] This message was edited by Chris Davison on 2002-09-15 08:07