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#0346
Web Only Users
EasySQL15 min10 XP
Problem
Return user_id values that appear in web_events but not app_events.
Why This Matters
SQL interviews usually test whether you can turn a business question into the right rows, grouping level, join type, and edge-case behavior.
Schema
web_events(user_id INTEGER); app_events(user_id INTEGER)
Examples
Example 1
Inputusers 1 and 3 are web-only
Output1, 3
EXCEPT removes users that appear in app_events.
Constraints
- Return only the requested columns.
- Use deterministic ORDER BY when multiple rows are returned.
- Assume SQLite-compatible SQL unless the prompt states otherwise.
CodeSQL
Visible browser tests run here when available.
Testcases1 visible / 3 hidden categories
Core SQL case
Inputusers 1 and 3 are web-only
Expected[[1],[3]]
EXCEPT removes users that appear in app_events.
Hidden Test Categories
Empty or missing matchesDuplicate rows or tiesNULL values where the pattern commonly breaks