Loading...
Join Type Row Counts
A easy SQL interview practice problem on DataDriven. Write and execute real sql code with instant grading.
- Domain
- SQL
- Difficulty
- easy
- Seniority
- junior, mid
Problem
Using the users and ad_impressions tables, write a single query that returns the row count produced by each combination type: inner, left, and full outer. Some users have no impressions, and some impressions have no associated user. Return each type as a label alongside its row count.
Practice This Problem
Solve this SQL problem with real code execution. DataDriven runs your SQL queries against a live PostgreSQL database and grades it instantly.