Compute article-type diversity per user and histogram
Quick Overview
This question evaluates data manipulation and aggregation skills, including joining event logs with metadata, deduplicating by categorical attribute, date-based filtering, and computing per-user distinct counts.
LinkedIn
Feb 1, 2026, 5:10 AM
Data Scientist
Technical Screen
Data Manipulation (SQL/Python)
2
0
You track article views and article metadata.
Tables
article_views
-
user_idINT -
article_idINT -
view_dateDATE
articles
-
article_idINT (PK) -
article_typeVARCHAR
Tasks
- For each user, compute the number of distinct article types they viewed on 2019-01-01 .
-
Output columns:
user_id,num_article_types.
-
Build a
histogram
of
num_article_typeson 2019-01-01 (i.e., how many users viewed 1 type, 2 types, etc.).
-
Output columns:
num_article_types,num_users.
Notes
- If a user viewed multiple articles of the same type, it counts once.
- Users with zero views on 2019-01-01 can be excluded unless otherwise specified.