MediumSQL challenge #136WHERE

Find Customers with at Least One Order Over 1,000

Return the distinct users who have placed at least one order above 1,000.

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.

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The task

Find users who placed at least one order above 1000.

A correct answer returns 102 rows with one column: user_id.

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
iduser_idtotaldiscountitem_countstatusorder_dateshipped_dateshipping_cityshipping_country
1432638.110.253cancelled2024-04-24NULLLos AngelesUSA
2829470.195delivered2024-03-152023-04-09ChicagoUSA
3136683.240.082delivered2023-02-152023-07-10Los AngelesUSA

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
43
8
115
140
50

First 5 of 102 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

  • Filtering rows with a WHERE condition
  • Removing duplicate rows with DISTINCT

Hint and approach

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

Show the hint

DISTINCT user_id

Show the step-by-step approach

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

  1. Read from the orders table.
  2. Filter in WHERE: keep the rows where total is greater than 1000.
  3. Return only the column user_id.
  4. DISTINCT removes duplicate rows, so each value appears once.

Model solution

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What to watch for

A customer with five large orders matches five times; DISTINCT reduces that to one row. This is the simplest way to express at least one, and EXISTS says the same thing when you need columns from the users table.

  • DISTINCT. DISTINCT works on the whole selected row. Adding one more column to the SELECT list can bring the duplicates back.
  • WHERE. WHERE is evaluated before the SELECT list, so it cannot use a column alias defined there or the result of an aggregate.
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