Please Note: This article is written for users of the following Microsoft Excel versions: 97, 2000, 2002, and 2003. If you are using a later version (Excel 2007 or later), this tip may not work for you. For a version of this tip written specifically for later versions of Excel, click here: Ensuring Unique Values in a Column.

Ensuring Unique Values in a Column

Written by Allen Wyatt (last updated September 14, 2022)
This tip applies to Excel 97, 2000, 2002, and 2003

1

When you are entering information in a worksheet, you may want to ensure that the data being entered is actually unique for a particular column. For instance, if you are entering a series of invoice numbers in column D of a worksheet, you may want to ensure that you don't enter the same invoice number twice.

There are a couple of ways that you can approach such a problem. If you are always entering your new information at the bottom of a column, you can use Excel's data validation feature to make sure that whatever you are entering in the current cell does not match anything higher up in the column. Simply follow these steps:

  1. Select column D.
  2. Choose Validation from the Data menu. Excel displays the Data Validation dialog box. (See Figure 1.)

    3. Figure 1. The Data Validation dialog box.

  3. Using the Allow drop-down list, choose the Custom option.
  4. In the Formula box, enter the following formula:
    5.      =MATCH(D1,$D:$D,0)=ROW(D1)
  5. Click on OK.

If you may be entering data anyplace within column D, and you want to know if you are entering a value that is elsewhere in the column (above or below the current cell), then you can follow the above steps, but use this formula in step 4:

=COUNTIF($D:$D,D1)<2

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (2650) applies to Microsoft Excel 97, 2000, 2002, and 2003. You can find a version of this tip for the ribbon interface of Excel (Excel 2007 and later) here: Ensuring Unique Values in a Column.

Author Bio

Allen Wyatt

With more than 50 non-fiction books and numerous magazine articles to his credit, Allen Wyatt is an internationally recognized author. He is president of Sharon Parq Associates, a computer and publishing services company. ...

MORE FROM ALLEN

Keeping Callouts Positioned

Using graphics to add callouts to your graphics is a common occurrence in Word. Here's how to stop all those graphics ...

Discover More

Deleting All Names but a Few

Want to get rid of most of the names defined in your workbook? You can either delete them one by one or use the handy ...

Discover More

Calculating Monthly Interest Charges

Trying to calculate how much people owe you? If you charge interest or service charges on past-due accounts, there are a ...

Discover More

Excel Smarts for Beginners! Featuring the friendly and trusted For Dummies style, this popular guide shows beginners how to get up and running with Excel while also helping more experienced users get comfortable with the newest features. Check out Excel 2013 For Dummies today!

More ExcelTips (menu)

Specifying a Data Validation Error Message

Data validation is a great tool for limiting what can be input into a cell. Excel allows you to specify what should ...

Discover More

Stopping Validated Data from being Overwritten

Data Validation is a great tool to make sure that data entered in a cell meets whatever criteria you decide. Its ...

Discover More

External Data Validation

When using data validation, you may want to reference a list of validation criteria contained on a different worksheet. ...

Discover More
Subscribe

FREE SERVICE: Get tips like this every week in ExcelTips, a free productivity newsletter. Enter your address and click "Subscribe."

View most recent newsletter.

(Your e-mail address is not shared with anyone, ever.)

Comments

If you would like to add an image to your comment (not an avatar, but an image to help in making the point of your comment), include the characters [{fig}] (all 7 characters, in the sequence shown) in your comment text. You’ll be prompted to upload your image when you submit the comment. Maximum image size is 6Mpixels. Images larger than 600px wide or 1000px tall will be reduced. Up to three images may be included in a comment. All images are subject to review. Commenting privileges may be curtailed if inappropriate images are posted.

What is four minus 0?

2020-04-02 11:31:29

Nigel Horne

Give me a heck of a lot of false positives. Doesn't work.

This Site

Got a version of Excel that uses the menu interface (Excel 97, Excel 2000, Excel 2002, or Excel 2003)? This site is for you! If you use a later version of Excel, visit our ExcelTips site focusing on the ribbon interface.

Newest Tips
Subscribe

FREE SERVICE: Get tips like this every week in ExcelTips, a free productivity newsletter. Enter your address and click "Subscribe."

(Your e-mail address is not shared with anyone, ever.)

View the most recent newsletter.

Links and Sharing
OUR COMPANY
OUR PRODUCTS
OUR SITES
 

Copyright © 2024 Sharon Parq Associates, Inc.