Data Validation List Without Duplicate
When you create a formatted Excel Table, you can use data validation to prevent within a column. In this Video, Unique list is entered in the column B, and each value much be unique.
ADD THE DATA VALIDATION:
- Select cells B:B
- On the Ribbon's Data tab, Click data validation
- On the settings tab from the Allow drop down, choose:Custom
- NOTE if there could be blank cells in the column, remove the check mark from "Ignore Blank Cells", or duplicates will be allowed
- In the formula box, you'll use the countif function to check value being entered in cell B2. It will be compared to all the entries in the Unique list column. To Prevent duplicates, the count must be 1 Or 0 "=countif($B:$B,B1)<2"