Why Removing duplicates in Google Sheets? - Purpose & Use Cases

The Big Idea

What if you could clean up messy lists in seconds instead of hours?

The Scenario

Imagine you have a long list of customer emails in a spreadsheet, but some emails appear more than once. You want to send a special offer, but you only want each customer to get one email.

The Problem

Manually scanning through hundreds or thousands of rows to find and delete repeated emails is slow and tiring. It's easy to miss duplicates or accidentally delete the wrong data, causing mistakes and frustration.

The Solution

Using the 'Removing duplicates' feature or formula in Google Sheets quickly finds and removes repeated entries. This saves time, reduces errors, and keeps your data clean and ready to use.

Before vs After

✗ Before

Scan rows one by one and delete duplicates manually

✓ After

=UNIQUE(A2:A100)

What It Enables

It lets you instantly get a clean list without repeats, making your data accurate and easier to work with.

Real Life Example

A small business owner wants to email all unique customers from a signup list that accidentally collected some emails twice. Removing duplicates ensures each customer gets only one email.

Key Takeaways

Manually removing duplicates is slow and error-prone.

Google Sheets can automatically find and remove duplicates.

This keeps your data clean and saves you time.

Practice

1. What does the UNIQUE(range) function do in Google Sheets?

easy

A. It highlights duplicate values in the range.

B. It sorts the values in the range alphabetically.

C. It counts how many times each value appears in the range.

D. It returns only the unique values from the given range, removing duplicates.

Solution

1. Step 1: Understand the purpose of UNIQUE()

   The UNIQUE() function is designed to filter out repeated values and return only distinct entries from a range.

2. Step 2: Compare options with UNIQUE() behavior

   'It returns only the unique values from the given range, removing duplicates.' correctly describes that UNIQUE() returns unique values by removing duplicates.

3. Final Answer:

   It returns only the unique values from the given range, removing duplicates. -> Option D

4. Quick Check:

   UNIQUE(range) = unique values [OK]

Hint: Remember: UNIQUE() filters duplicates, not sorting or counting [OK]

Common Mistakes:

• Confusing UNIQUE() with SORT()
• Thinking UNIQUE() counts duplicates
• Assuming UNIQUE() highlights duplicates

2. Which of these is the correct syntax to remove duplicates from the range A1:A10 in Google Sheets?

easy

A. FILTER_DUPLICATES(A1:A10)

B. REMOVE_DUPLICATES(A1:A10)

C. UNIQUE(A1:A10)

D. DELETE_DUPLICATES(A1:A10)

Solution

1. Step 1: Identify the correct function name

   Google Sheets uses UNIQUE() to remove duplicates, not any other function names.

2. Step 2: Check the syntax format

   The correct syntax is UNIQUE(range), so UNIQUE(A1:A10) is valid and works as expected.

3. Final Answer:

   UNIQUE(A1:A10) -> Option C

4. Quick Check:

   Correct syntax = UNIQUE(range) [OK]

Hint: Use UNIQUE() exactly, no other function removes duplicates [OK]

Common Mistakes:

• Using non-existent functions like REMOVE_DUPLICATES()
• Adding extra parentheses or commas incorrectly
• Confusing with FILTER() function

3. Given the data in cells A1:A6 as:
1
2
2
3
1
4
What will be the result of =UNIQUE(A1:A6)?

medium

A. [1, 2, 3, 4]

B. [1, 2, 2, 3, 1, 4]

C. [4, 3, 2, 1]

D. [1, 3, 4]

Solution

1. Step 1: List unique values from the data

   The values are 1, 2, 2, 3, 1, 4. Unique values in order of first appearance are 1, 2, 3, 4.

2. Step 2: Understand UNIQUE() output

   UNIQUE() returns these unique values as a vertical array: 1, 2, 3, 4.

3. Final Answer:

   [1, 2, 3, 4] -> Option A

4. Quick Check:

   UNIQUE removes duplicates, keeps first order [OK]

Hint: UNIQUE() keeps first occurrence, removes repeats [OK]

Common Mistakes:

• Expecting sorted output instead of original order
• Including duplicates in the result
• Confusing UNIQUE() with SORT()

4. You wrote =UNIQUE(A1:A5, TRUE, FALSE, TRUE) but get an error. What is wrong?

medium

A. TRUE should be FALSE to remove duplicates.

B. UNIQUE() takes at most three arguments, extra TRUE causes error.

C. The range A1:A5 is invalid for UNIQUE().

D. UNIQUE() requires a second argument to work.

Solution

1. Step 1: Check UNIQUE() function arguments

   UNIQUE() accepts one required argument (range) and up to two optional boolean arguments ([by_column], [exactly_once]). Adding a fourth TRUE is invalid syntax.

2. Step 2: Understand error cause

   Passing more than three arguments causes a formula parse error in Google Sheets.

3. Final Answer:

   UNIQUE() takes at most three arguments, extra TRUE causes error. -> Option B

4. Quick Check:

   UNIQUE(range[, by_col][, exact]) only up to 3 args [OK]

Hint: UNIQUE() takes at most 3 arguments, no extras [OK]

Common Mistakes:

• Adding extra arguments to UNIQUE()
• Thinking TRUE/FALSE controls duplicate removal
• Using invalid ranges

5. You have a table with columns A (Name) and B (City) from rows 1 to 8. Some rows have duplicate Name and City pairs. Which formula removes duplicate rows considering both columns together?

hard

A. UNIQUE(A1:B8)

B. UNIQUE(A1:A8)

C. UNIQUE(B1:B8)

D. UNIQUE(A1:B8, TRUE)

Solution

1. Step 1: Understand removing duplicates by multiple columns

   To remove duplicates based on both Name and City, you must include both columns in the UNIQUE() range.

2. Step 2: Check options for correct range

   UNIQUE(A1:B8) uses UNIQUE(A1:B8), which considers both columns together and removes duplicate rows correctly.

3. Final Answer:

   UNIQUE(A1:B8) -> Option A

4. Quick Check:

   UNIQUE(multi-column range) removes duplicate rows [OK]

Hint: Include all columns in UNIQUE() to remove full-row duplicates [OK]

Common Mistakes:

• Using only one column range to remove multi-column duplicates
• Adding extra arguments to UNIQUE()
• Expecting UNIQUE() to sort automatically