#0140

Users With No Events

EasySQL15 min10 XP

Problem

Return user_id and name for users with no events.

Anti-joins are critical for churn, inactive users, missing records, and data-quality checks.

users(user_id INTEGER, name TEXT); events(event_id INTEGER, user_id INTEGER)

Example 1

Inputusers 1,2 and only user 1 has an event

Outputuser 2

The left join creates NULL event columns for users with no match.

CodeSQL

SELECT
  -- write your code here
  user_id,
  name
FROM users;

SELECT
  -- write your code here
  user_id,
  name
FROM users;

Visible browser tests run here when available.

Testcases1 visible / 3 hidden categories

Core example

Inputusers 1,2 and only user 1 has an event

Expecteduser 2

The left join creates NULL event columns for users with no match.

Hidden Test Categories

all users activemultiple events per userno events table rows