EasySQL challenge #7DISTINCT

List Unique Cities with SELECT DISTINCT

List every city that appears in the users table, each one only once.

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

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The task

Find distinct cities from users.

A correct answer returns 20 rows with one column: city.

Tables used in this challenge

users 150 rows

id INTEGER (PK) · first_name TEXT · last_name TEXT · email TEXT · phone TEXT · city TEXT · country TEXT · created_at TEXT · status TEXT · is_premium INTEGER

First 3 rows of the users table
idfirst_namelast_nameemailphonecitycountrycreated_atstatusis_premium
1JenniferTorresjennifer.torres57@icloud.com+1-263-376-2371HoustonCanada2024-04-13active0
2DonnaAdamsdonna.adams52@gmail.com+1-753-780-6670Fort WorthCanada2020-09-15inactive0
3KennethYoungkenneth.young94@proton.me+1-440-743-9503AustinUSA2023-09-05active0

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
city
Houston
Fort Worth
Austin
San Antonio
New York

First 5 of 20 rows. This is the output of the model solution on the practice database. The task does not fix a sort order, so your rows may come back in a different order.

What you practise

  • Removing duplicate rows with DISTINCT

Hint and approach

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

Show the hint

Use DISTINCT

Show the step-by-step approach

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

  1. Read from the users table.
  2. Return only the column city.
  3. DISTINCT removes duplicate rows, so each value appears once.

Model solution

Checking your session…

What to watch for

DISTINCT applies to the whole selected row, not to one column. Add a second column and you get unique pairs, which is usually more rows than you expected.

  • DISTINCT. DISTINCT works on the whole selected row. Adding one more column to the SELECT list can bring the duplicates back.
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Same technique, other tables

More practice on this pattern with different columns:

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