Learn SQL Subqueries: THE DIRECTOR

THE DIRECTOR is chapter 13, the subqueries chapter. ACCESS_LOGS records every classified file an analyst touched; ANALYSTS holds the personnel. You nest one SELECT inside another, using IN to find analysts who reached top-secret material and NOT IN to clear the ones who never did.

The final stage raises the bar: compare each analyst's activity against the average, which means feeding an aggregate subquery into your filter. Writing a query inside a query is the moment SQL starts feeling like a real language.

The subqueries and EXISTS guide linked below is the recommended pre-read.

This is the shape of query you practice here, not the answer to any mission. The real stages come with their own data, objectives, and hints.

SELECT NAME, DEPARTMENT
FROM ANALYSTS
WHERE ID IN (
  SELECT ANALYST_ID FROM ACCESS_LOGS WHERE CLASSIFICATION = 'SIGMA'
);

Free guides that pair well with this chapter:

• GROUP BY and HAVING: The Difference Explained
• Subqueries and EXISTS: Correlated vs Non-Correlated