关键字
只要其中某个表存在匹配，FULL JOIN 关键字就会返回行。
FULL JOIN 关键字语法
SELECT column_name(s) FROM table_name1 FULL JOIN table_name2 ON table_name1.column_name=table_name2.column_name 注释：在某些数据库中， FULL JOIN 称为 FULL OUTER JOIN。
原始的表
"Persons" 表：
|
Id_P
|
LastName
|
FirstName
|
Address
|
City
|
|---|---|---|---|---|
|
1
|
Adams
|
John
|
Oxford Street
|
London
|
|
2
|
Bush
|
George
|
Fifth Avenue
|
New York
|
|
3
|
Carter
|
Thomas
|
Changan Street
|
Beijing
|
"Orders" 表：
|
Id_O
|
OrderNo
|
Id_P
|
|---|---|---|
|
1
|
77895
|
3
|
|
2
|
44678
|
3
|
|
3
|
22456
|
1
|
|
4
|
24562
|
1
|
|
5
|
34764
|
65
|