Write a SQL query joining two tables on a key column.

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Accepted Answer

Joining two tables in SQL allows you to combine related data for more comprehensive queries.

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

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