Hello, Can someone help me with creating a data validation rule to stop duplicates across selected columns in a worksheet.
I need to create unique numbers in certain columns. Other columns will be allowed duplicates. For example I will need to prevent any duplicates occurring in Columns F,I, L and O wherever there is data entered.
I have been successful in creating the COUNTIF rule for a range of numbers but not if the columns are separated.
Would be very grateful if someone can help me with this, many thanks
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