Oracle数据库的连接查询

EMPL EMPLOYEE_NAME DEPARTMENT_ID---- -------------------- -------------1001 jack 11002 tom 21003 smith 21004 rose 3

DEPARTMENT_ID DEPARTMENT_NAME DEPARTMENT_LOCATION------------- -------------------- ----------------------- 1 公寓1 ss 2 公寓2 sa 3 公寓3 sb 4 公寓4 sv

SQL> select e.employee_name,e.department_id,d.department_name 2 from employee e,department d 3 where e.department_id=d.department_id;

EMPLOYEE_NAME DEPARTMENT_ID DEPARTMENT_NAME-------------------- ------------- --------------------jack 1 公寓1smith 2 公寓2tom 2 公寓2rose 3 公寓3

SQL> select e.employee_name,e.department_id,d.department_name 2 from employee e,department d 3 where e.department_id=d.department_id(+);EMPLOYEE_NAME DEPARTMENT_ID DEPARTMENT_NAME-------------------- ------------- --------------------jack 1 公寓1smith 2 公寓2tom 2 公寓2rose 3 公寓3

SQL> select e.employee_name,e.department_id,d.department_name 2 from employee e,department d 3 where e.department_id(+)=d.department_id;EMPLOYEE_NAME DEPARTMENT_ID DEPARTMENT_NAME-------------------- ------------- --------------------jack 1 公寓1tom 2 公寓2smith 2 公寓2rose 3 公寓3 公寓4

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