转自:http://xsb.itpub.net/post/419/54491
ORACLE 8i,9i 表连接方法。
一般的相等连接: select * from a, b where a.id = b.id; 这个就属于内连接。
对于外连接: Oracle中可以使用“(+) ”来表示,9i可以使用LEFT/RIGHT/FULL OUTER JOIN
LEFT OUTER JOIN:左外关联 SELECT e.last_name, e.department_id, d.department_name FROM employees e LEFT OUTER JOIN departments d ON (e.department_id = d.department_id); 等价于 SELECT e.last_name, e.department_id, d.department_name FROM employees e, departments d W......
阅读全文