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MySQL JOINs with Subqueries

Subqueries can be used in join operations to create more complex queries. They allow you to filter or aggregate data before performing the join.

Example: Using Subquery in a JOIN

SELECT kings.king_name, kingdoms.kingdom_name
FROM (SELECT king_id, king_name, kingdom_id FROM tamil_kings WHERE reign_start > 900) AS kings
JOIN kingdoms ON kings.kingdom_id = kingdoms.kingdom_id;

Code Explanation: This query uses a subquery to filter kings who started their reign after 900 AD and then joins the result with the kingdoms table.

Key Takeaways

  • Subqueries in joins can be used to filter or aggregate data before joining.
  • They provide flexibility in writing complex SQL queries.
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