JOIN

Description

The JOIN statement is used to combine rows from two or more tables.

The following figure shows seven usages of LEFT JOIN, RIGHT JOIN, INNER JOIN, and OUTER JOIN.

• LEFT JOIN

SELECT / FROM TableA A LEFT JOIN TableB B ON A.Key=B.Key
SELECT / FROM TableA A LEFT JOIN TableB B ON A.Key=B.Key WHERE B.Key IS NULL

• RIGHT JOIN

SELECT / FROM TableA A RIGHT JOIN TableB B ON A.Key=B.Key
SELECT / FROM TableA A RIGHT JOIN TableB B ON A.Key=B.Key WHERE A.Key IS NULL

• INNER JOIN

SELECT / FROM TableA A INNER JOIN TableB B ON A.Key=B.Key

• FULL JOIN

SELECT / FROM TableA A FULL OUTER JOIN TableB B ON A.Key=B.Key
SELECT / FROM TableA A FULL OUTER JOIN TableB B ON A.Key=B.Key WHERE A.Key IS NULL OR B.Key IS NULL

For more information, see the reference below:

• LEFT JOIN
• RIGHT JOIN
• INNER JOIN
• FULL JOIN
• OUTER JOIN
• NATURAL JOIN