MediumSQL challenge #131GROUP BYORDER BY

Find the Top 5 Customers by Total Spend

Return the five users with the highest combined order value.

The challenge runs on the SQLabHub practice database (SQLite) and uses the orders table. You can solve it in the browser, with nothing to install.

Solve This SQL Challenge

The task

Find top 5 users based on total spending.

A correct answer returns 5 rows with 2 columns: user_id, spend.

Tables used in this challenge

`orders` 200 rows

id INTEGER (PK) · user_id INTEGER · total REAL · discount REAL · item_count INTEGER · status TEXT · order_date TEXT · shipped_date TEXT · shipping_city TEXT · shipping_country TEXT

First 3 rows of the orders table
id	user_id	total	discount	item_count	status	order_date	shipped_date	shipping_city	shipping_country
1	43	2638.11	0.25	3	cancelled	2024-04-24	NULL	Los Angeles	USA
2	8	2947	0.19	5	delivered	2024-03-15	2023-04-09	Chicago	USA
3	136	683.24	0.08	2	delivered	2023-02-15	2023-07-10	Los Angeles	USA

The first rows of each table are shown. See how all the tables relate on the database schema page.

Expected output

Expected output of the challenge
user_id	spend
118	15384.26
77	14593.17
124	12059.32
98	11837.52
54	11780.529999999999

The complete result: 5 rows. This is the output of the model solution on the practice database.

What you practise

Summarising many rows into one value with COUNT, SUM, AVG, MIN or MAX
Grouping rows with GROUP BY to get one result row per group
Sorting the result with ORDER BY
Returning only the first rows with LIMIT

Hint and approach

Try the challenge first. Open these only when you need them.

Show the hint

SUM(total) ORDER BY DESC LIMIT

Show the step-by-step approach

How the model solution is built, in the order the database evaluates it:

Read from the orders table.
Group the rows by user_id, so the result has one row for each value.
For each group, compute SUM(total).
Sort the result by spend descending.
Keep only the first 5 rows with LIMIT.

Model solution

Checking your session…

What to watch for

Three steps in a fixed order: aggregate per user, sort by the aggregate, then limit. LIMIT applies last, after the totals exist.

GROUP BY. Every selected column must either be in GROUP BY or sit inside an aggregate. SQLite accepts other columns and returns an arbitrary value for them; most databases raise an error.
LIMIT. LIMIT without ORDER BY returns an arbitrary set of rows. LIMIT is also dialect-specific: SQL Server uses TOP and Oracle uses FETCH FIRST.
ORDER BY. Without ORDER BY the row order is not guaranteed, even if it looks stable. Rows that tie on the sort columns can come back in any order.

Solve This SQL Challenge

Find the Top 15 Customers by Lifetime RevenueSimilar levelMedium
Build a Monthly Revenue Report Excluding Cancelled OrdersSimilar levelMedium
Count Orders by Status with GROUP BYEasierEasy
Find the City with the Highest Total RevenueHarderHard
Find the Week with the Highest RevenueHarderHard

Same technique, other tables

More practice on this pattern with different columns:

Keep learning

Lesson: GROUP BY
Lesson: LIMIT / TOP / FETCH
Lesson: ORDER BY
Lesson: Aggregate Functions
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