FULL OUTER JOIN 關鍵字只要左表（table1）和右表（table2）其中一個表中存在匹配，則返回行.

FULL OUTER JOIN 關鍵字結合了 LEFT JOIN 和 RIGHT JOIN 的結果。

SQL FULL OUTER JOIN 語法

SELECT column_name(s)
FROM table1
FULL OUTER JOIN table2
ON table1.column_name=table2.column_name;

示例：

SELECT Websites.name, access_log.count, access_log.date
 

FROM Websites
FULL OUTER JOIN access_log
ON Websites.id=access_log.site_id
ORDER BY access_log.count DESC;