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SQL / CHAPTER 05
SQL
Advanced queries.
Learn SQL with real tables and PostgreSQL in your browser. Learn and Practice per topic, separate challenges.
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Lesson with explanation and a guided task. Theory stays readable; completion requires a passing solution.
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11 lessons available
The foundations behind your ideas.
- 01Open lesson
CASE WHEN: categories · Locked
CASE WHEN: categories
- 02Open lesson
Scalar subquery · Locked
Scalar subquery
- 03Open lesson
IN with a subquery · Locked
IN with a subquery
- 04Open lesson
EXISTS · Locked
EXISTS
- 05Open lesson
Correlated subquery · Locked
Correlated subquery
- 06Open lesson
NOT IN, NULL and NOT EXISTS · Locked
NOT IN, NULL and NOT EXISTS
- 07Open lesson
Subquery in FROM · Locked
Subquery in FROM
- 08Open lesson
CTE with WITH · Locked
CTE with WITH
- 09Open lesson
Sequential CTEs · Locked
Sequential CTEs
- 10Open lesson
UNION and UNION ALL · Locked
UNION and UNION ALL
- 11Open lesson
Monthly report · Locked
Monthly report