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SQLBeginner#fundamentals
SQLIntermediate#joins
What is the difference between a natural join and an equi join?
An equi join states the equality condition explicitly in ON. A natural join implicitly joins on all identically named columns, which is concise but fragile when schemas change.
Example
-- equi join (preferred) SELECT * FROM employees e JOIN departments d ON e.dept_id = d.dept_id; -- natural join SELECT * FROM employees NATURAL JOIN departments;