Join

A join is the process of combining data from two or more tables using matching columns.

Examples

SELECT * FROM emp, dept
WHERE  emp.deptno = dept.deptno;

SELECT * FROM dept
  INNER JOIN emp ON (emp.deptno = dept.deptno);

SELECT * FROM emp NATURAL JOIN dept;

Also see

Join methods:

• Cartesian join
• Equi join
• Inner join
• Natural join
• Nonequi join
• Outer join
• Self join

Join optimizations:

• Cluster join
• Hash join
• Nested loops join
• Sort merge join

Glossary of Terms
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