如何使用ID作为外键显示名称？

Question

这就是我所拥有的：

我有一个名为Area的表，它是自引用的。如果列ParentAreaID为null，则表示它是父区域。如果它有值，则表示它有父母。

如何显示包含ID，姓名和名称的表（使用自引用ID的父母）？

Answer 1

您想使用connect by：http://psoug.org/reference/connectby.html

create table sample (id number, parentid number, name varchar2(50));

insert into sample values(1,null,'aaa');
insert into sample values(2,NULL,'bbb');
insert into sample values(3,NULL,'ccc');
insert into sample values(4,null,'ddd');

insert into sample values(5,1,'aaa1');
insert into sample values(6,2,'bbb2');
insert into sample values(7,3,'ccc3');
insert into sample values(8,4,'ddd4');

insert into sample values(9,5,'aaa11');
insert into sample values(10,6,'bbb22');
insert into sample values(11,7,'ccc33');
insert into sample values(12,8,'ddd44');

SELECT ID,PARENTID, NAME, CONNECT_BY_ROOT NAME PARENTNAME,
 SYS_CONNECT_BY_PATH(name, '/')
  FROM SAMPLE
  start with parentid is null
 CONNECT BY PRIOR ID = PARENTID
 order siblings by id;