Multi-Column duplicate search

**AP19** · 07-09-2013, 11:08 AM

Hey let me first say this is a great forum with tons of helpful advice and I know this is a common subject but I haven’t been able to get any of the solutions I've found thus far to work the way I need them to.

OK so the issue is I have 15 months of data with each month separated into a new column. I need a formula that will search each previous month’s columns for duplicate values in order to determine the amount of unique values. For example if the value 5 appears in the June column I would need the formula to search May, April, and March for the number 5 and if it appears label the new cell duplicate and if it doesn’t appear label the new cell unique.

Thank you in advance for any help and effort.

**Fotis1991** · 07-09-2013, 11:29 AM

Looks like SUMPRODUCT issue, but it's better to upload a small sample workbook.

To attach a small sample workbook.

Click on GO ADVANCED and use the paperclip icon to open the upload window.

View Pic

**AP19** · 07-09-2013, 11:47 AM

Small sample, hope this helps.

**Fotis1991** · 07-09-2013, 11:57 AM

I use conditinal formatting to highlight the numbers that exist in previous months.

=COUNTIF($A2:A20;B2)>0

**AP19** · 07-09-2013, 12:20 PM

Thank you so much it looks to be working great so far!

**Fotis1991** · 07-09-2013, 12:21 PM

You are welcome and thanks for the feed back.

As that takes care of your original question, please select Thread Tools from the menu link above and mark this thread as SOLVED. Thank you.

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