Using the UNIQUE Function

Danny is unclear on how the UNIQUE worksheet function is used. He questions whether it only works with numbers, or will it work with text. He is particularly interested in how many characters in text values it might compare.

The UNIQUE function was added in the version of Excel provided with Microsoft 365. It is one of the rather unique (no pun intended) database functions now available in Excel. It is designed to analyze a range of cells and return the unique values in that range. It will work with any primary data type that Excel supports—numbers, text, dates, times, etc.

This is the syntax of the UNIQUE function:

UNIQUE(Range, Direction, ExactlyOnce)

According to this syntax, the UNIQUE function can use up to 3 parameters. Only one of those parameters is mandatory, however, and that is the Range parameter. This one indicates the range of cells you want UNIQUE to evaluate. The function returns an array of values, so that it spills over into whatever cells are available beneath the cell in which the function is used.

If the Range is a single column, then the unique values in that column are returned. When evaluating text values, UNIQUE doesn't pay attention to whether the text is uppercase or lowercase; it is all treated the same. Plus, length of the text is not a factor.

If the Range you specify is multiple columns (such as A2:B19), then UNIQUE analyzes the range as if it were a single column. For instance, if A6:B6 is "Frank, 12," and A12:B12 is "Frank, 41," then UNIQUE includes rows for both in what it returns—the key isn't on the uniqueness of the first column, but on the total uniqueness of all columns, considered together.

This understanding of the way that the Range parameter is understood can come in handy. Let's say that you have a list of names, with the last name being in column A and the first name being in column B. There are duplicates in the list, but you want the unique names to be determined. You could, if desired, derive the unique values in this way:

=UNIQUE(B2:B49&" "&A2:A49)

What gets returned is the unique names, in the form of first name, space, last name. If you prefer to have them with last name first, you could just as easily have used this variation:

=UNIQUE(A2:A49&", "&B2:B49)

You could even take it a step further and sort the names by wrapping the whole thing in the SORT function:

=SORT(UNIQUE(A2:A49&", "&B2:B49))

Back to the UNIQUE function, however. The second parameter (Direction) can be either True or False. The default for this parameter is False, which means that you are evaluating values downward, in a single column (or in an aggregated column, as described earlier). If you want to evaluate values across a row, you would set this parameter to True, as shown here:

=UNIQUE(A2:Q2,True)

The third parameter (ExactlyOnce) is the really interesting parameter. Like the Direction parameter, ExactlyOnce can be either True or False. The ExactlyOnce parameter also defaults to False, which means that all unique values are returned from the Range. If you set this parameter to True, however, then UNIQUE returns values from the Range that occur only once in that range.

As an example, let's say you had a bunch of transactions in the range A1:K1459. The first row is for column headers, and column A contains an account number for each transaction. These transactions are for the last six months, and your boss wants you to figure out which accounts made only a single transaction during that time so that you can offer them a special incentive to purchase again. You could use the following formula to determine the desired accounts:

=UNIQUE(A2:A1459,,True)

You end up with just those account numbers you need—the ones that purchased only once during the last six months.

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (12835) applies to Microsoft Excel Excel in Microsoft 365 and 2021.