Access/SQL Server/Oracle 左连接、右连接、外连接、内连接

Access：
SELECT A.id,A.name,B.dep,C.class
FROM (test01 AS A LEFT JOIN test02 as B on A.id=B.id) LEFT JOIN test03 AS C on A.id=C.id

SQL Server：
SELECT A.id,A.name,B.dep,C.class
FROM test01 AS A LEFT OUTER JOIN test02 as B on A.id=B.id LEFT OUTER JOIN test03 AS C on A.id=C.id
或 
右连接：
SELECT Student .sno,Sname,Ssex,Sage,Cno,Grade FROM Student ,SC WHERE Student.Sno=SC.Sno(*);
左连接：
SELECT Student .sno,Sname,Ssex,Sage,Cno,Grade FROM Student ,SC WHERE Student.Sno(*)=SC.Sno;


Oracle：
SELECT A.id,A.name,B.dep,C.class
FROM test01 A,test02 B,test03 C
WHERE A.id=B.id(+) AND A.id=C.id(+)

或：
SELECT A.id,A.name,B.dep,C.class
FROM test01 A LEFT OUTER JOIN test02 B on (A.id=B.id) LEFT OUTER JOIN test03 C on (A.id=C.id)

注：SqlServer与Oracle左右连接中的OUTER可以省略。

内连接关键字：...inner join...on...