Write some SQL queries that require the use of joins.

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Accepted Answer

SQL joins combine rows from two or more tables based on related columns.

INNER JOIN: Returns records with matching values in both tables. Example: SELECT * FROM A INNER JOIN B ON A.id = B.a_id;
LEFT JOIN: Returns all records from the left table and matched records from the right table. Example: SELECT * FROM A LEFT JOIN B ON A.id = B.a_id;
RIGHT JOIN: Returns all records from the right table and matched records from the left table. Example: SELECT * FROM A RIGHT JOIN B ON A.id = B.a_id;
FULL OUTER JOIN: Returns all records when there is a match in either left or right table. Example: SELECT * FROM A FULL OUTER JOIN B ON A.id = B.a_id;

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