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#0340

Funnel Step Counts

MediumSQL24 min20 XP

Problem

Return step and users_count for each event_name.

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

events(user_id INTEGER, event_name TEXT)

Examples

Example 1
Inputvisit/signup/purchase events
Outputvisit 3, signup 2, purchase 1

COUNT DISTINCT avoids double-counting repeated events from the same user.

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
Inputvisit/signup/purchase events
Expected[["purchase",1],["signup",2],["visit",3]]

COUNT DISTINCT avoids double-counting repeated events from the same user.

Hidden Test Categories
Empty or missing matchesDuplicate rows or tiesNULL values where the pattern commonly breaks