GROUP BY with aggregation in Google Sheets - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the GROUP BY clause do in a query?

GROUP BY groups rows that have the same values in specified columns into summary rows, like grouping all sales by each product.

beginner

Which function would you use to find the total sum of a column after grouping?

You use the SUM() function to add up values in a column for each group.

intermediate

How do you write a query to count the number of entries per category in Google Sheets QUERY function?

Use: SELECT Category, COUNT(Column) GROUP BY Category

beginner

Why do you need to use GROUP BY when using aggregation functions?

Because aggregation functions like SUM or COUNT summarize data per group, GROUP BY tells the query how to group rows before summarizing.

intermediate

In Google Sheets QUERY, what happens if you use an aggregation function without GROUP BY?

The aggregation function will calculate over the entire data set, returning a single summary value instead of grouped results.

What does the GROUP BY clause do in a Google Sheets QUERY?

A Filters rows based on a condition

B Deletes duplicate rows

C Sorts rows alphabetically

D Groups rows with the same values in specified columns

GROUP BY groups rows that share the same values in specified columns to prepare for aggregation.

Which aggregation function counts the number of rows in each group?

A COUNT()

B MAX()

C SUM()

D MIN()

COUNT() counts the number of rows or non-empty values in each group.

What will this QUERY return? SELECT Category, SUM(Sales) GROUP BY Category

A All sales rows without grouping

B Total sales for each category

C Sum of all sales without grouping

D Number of categories

It sums sales values for each category separately.

If you forget to add GROUP BY when using SUM(), what happens?

A SUM() returns zero

B You get an error

C SUM() sums all rows ignoring groups

D SUM() counts rows instead

Without GROUP BY, SUM() calculates the total over all rows.

Which of these is a valid Google Sheets QUERY with grouping?

A SELECT Name, COUNT(Age) GROUP BY Name

B SELECT Name, COUNT(Age)

C SELECT COUNT(Age) GROUP BY Name

D SELECT Name, Age

When using COUNT() with another column, you must GROUP BY that column.

Explain how GROUP BY works with aggregation functions in Google Sheets QUERY.

Think about how you would summarize sales by product category.

Describe a real-life example where you would use GROUP BY with SUM in Google Sheets.

Imagine you want to know total sales per product.