How do you count unique paying customers per month?

Problem Statement

Explanation

COUNT(DISTINCT col) deduplicates values before counting. It is ideal when multiple rows per customer exist. If you also group by month, you get unique customers per month.

Code Solution

SolutionRead Only

SELECT date_trunc('month', paid_at) AS mon,
       COUNT(DISTINCT customer_id) AS unique_buyers
FROM payments
GROUP BY date_trunc('month', paid_at);

Practice Sets

This question appears in the following practice sets:

Filtering, Grouping & Aggregations

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How do you count unique paying customers per month?

Problem Statement

Explanation

Code Solution

Practice Sets

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Master Interviews Anywhere, Anytime

How do you count unique paying customers per month?

Problem Statement

Explanation

Code Solution

Practice Sets

Related Questions

Which SQL statement retrieves all columns and rows from a table named employees?

Which clause filters rows before aggregation and affects which rows are grouped?

What is the default sort order when ORDER BY is used without ASC or DESC?

Which construct is commonly used to paginate results in SQL engines like Postgres and MySQL?

Which predicate correctly checks for missing values in standard SQL?

More from SQL & Databases

Master Interviews
Anywhere, Anytime