Role track
Data Architect
Grain, cost, and paved roads. You still have to query the mart you designed.
172 questions · SQL · Warehouse · System design · Cloud · Behavioral
Suggested sequence
1. Hard SQL
Division, sessions, lag, nested averages — the mart you would certify.
Architect coding →2. The flowchart
Warehouse vs lakehouse, governance people use, migrations without heroics.
Architect roadmap →3. Platform sketch
CDC, gold grain, who pages, who pays.
System design →4. Saying no
A time two revenues existed. What you killed.
Behavioral →
Stacks in this loop
Sample questions
hard · SQL · Stripe
Deduplicate to the latest customer row. Why not filter the window in WHERE?
Practice →medium · SQL · Capital One
A join exploded revenue. How do you find the grain mismatch in five minutes?
Practice →medium · SQL · Meta
Running total of daily revenue. Why is SUM(SUM(amount)) OVER (...) valid?
Practice →hard · SQL · Google
NULL = NULL is unknown. How does that bite a MERGE or an anti-join?
Practice →hard · SQL · LinkedIn
When do you use a covering index / clustering key versus rewriting the query?
Practice →medium · SQL · Snowflake
QUALIFY vs a CTE for window filters — when do you use each?
Practice →