oracle 9i判斷是葉子或根節點，是比較麻煩的一件事情，SQL演示腳本如下:

view plaincopy to clipboardprint?

DROP?TABLE?idb_hierarchical;??

create?TABLE?idb_hierarchical??

(??

id?number,??

parent_id?number,??

str?varchar2(10)??

);??

??

insert?into?idb_hierarchical?values(1,null,'A');??

insert?into?idb_hierarchical?values(2,1,'B');??

insert?into?idb_hierarchical?values(3,2,'C');??

insert?into?idb_hierarchical?values(4,3,'D');??

insert?into?idb_hierarchical?values(5,2,'E');??

insert?into?idb_hierarchical?values(6,2,'F');??

insert?into?idb_hierarchical?values(7,3,'G');??

insert?into?idb_hierarchical?values(8,4,'H');??

insert?into?idb_hierarchical?values(9,4,'I');??

insert?into?idb_hierarchical?values(10,null,'J');??

insert?into?idb_hierarchical?values(11,10,'K');??

insert?into?idb_hierarchical?values(12,11,'L');??

insert?into?idb_hierarchical?values(13,10,'M');??

DROP TABLE idb_hierarchical; create TABLE idb_hierarchical ( id number, parent_id number, str varchar2(10) );insert into idb_hierarchical values(1,null,'A'); insert into idb_hierarchical values(2,1,'B'); insert into idb_hierarchical values(3,2,'C'); insert into idb_hierarchical values(4,3,'D'); insert into idb_hierarchical values(5,2,'E'); insert into idb_hierarchical values(6,2,'F'); insert into idb_hierarchical values(7,3,'G'); insert into idb_hierarchical values(8,4,'H'); insert into idb_hierarchical values(9,4,'I'); insert into idb_hierarchical values(10,null,'J'); insert into idb_hierarchical values(11,10,'K'); insert into idb_hierarchical values(12,11,'L'); insert into idb_hierarchical values(13,10,'M');

示例數據清單如下:

view plaincopy to clipboardprint?

SELECT?RPAD('+',LEVEL*2+1,'.')||STR?STR_LEVEL,ID,PARENT_ID,LEVEL?LVL??

??FROM?idb_hierarchical??

?START?WITH?PARENT_ID?IS?NULL??

CONNECT?BY?PARENT_ID?=?PRIOR?ID;??

SELECT RPAD('+',LEVEL*2+1,'.')||STR STR_LEVEL,ID,PARENT_ID,LEVEL LVLFROM idb_hierarchicalSTART WITH PARENT_ID IS NULL CONNECT BY PARENT_ID = PRIOR ID; 表1:數據清單STR_LEVELIDPARENT_IDLVL

+..A	1	?	1
+….B	2	1	2
+……C	3	2	3
+……..D	4	3	4
+……….H	8	4	5
+……….I	9	4	5
+……..G	7	3	4
+……E	5	2	3
+……F	6	2	3
+..J	10	?	1
+….K	11	10	2
+……L	12	11	3
+….M	13	10	2

在表1中，ID為8、9、 7、5、6、12、13都沒有子節點，因此稱為葉節點。

1.oracle9i 查詢葉節點

只顯示葉子節點SQL

view plaincopy to clipboardprint?

SELECT?RPAD('+',LEVEL*2+1,'.')||STR?STR_LEVEL,ID,PARENT_ID,LEVEL?LVL??

??FROM?idb_hierarchical?I??

??--在oracle?9i中顯示葉節點，需要判斷是否有子節點即可??

??WHERE?NOT?EXISTS(SELECT?1??

??FROM?idb_hierarchical?B??

??WHERE?I.ID=B.PARENT_ID)??

?START?WITH?PARENT_ID?IS?NULL??

CONNECT?BY?PARENT_ID?=?PRIOR?ID;??

SELECT RPAD('+',LEVEL*2+1,'.')||STR STR_LEVEL,ID,PARENT_ID,LEVEL LVLFROM idb_hierarchical I--在oracle 9i中顯示葉節點，需要判斷是否有子節點即可WHERE NOT EXISTS(SELECT 1FROM idb_hierarchical BWHERE I.ID=B.PARENT_ID)START WITH PARENT_ID IS NULL CONNECT BY PARENT_ID = PRIOR ID; 表2

STR_LEVEL	ID	PARENT_ID	LVL
+……….H	8	4	5
+……….I	9	4	5
+……..G	7	3	4
+……E	5	2	3
+……F	6	2	3
+……L	12	11	3
+….M	13	10	2

顯示所有節點，標明該行是否為葉節點SQL

view plaincopy to clipboardprint?

SELECT?RPAD('+',LEVEL*2+1,'.')||STR?STR_LEVEL,ID,PARENT_ID,LEVEL?LVL,??

NVL((SELECT?'N'??

??FROM?idb_hierarchical?B??

??WHERE?I.ID=B.PARENT_ID??

??AND?ROWNUM??<?2),'Y')?IS_LEAF??

??FROM?idb_hierarchical?I??

?START?WITH?PARENT_ID?IS?NULL??

CONNECT?BY?PARENT_ID?=?PRIOR?ID;??

SELECT RPAD('+',LEVEL*2+1,'.')||STR STR_LEVEL,ID,PARENT_ID,LEVEL LVL, NVL((SELECT 'N'FROM idb_hierarchical BWHERE I.ID=B.PARENT_IDAND ROWNUM < 2),'Y') IS_LEAFFROM idb_hierarchical ISTART WITH PARENT_ID IS NULL CONNECT BY PARENT_ID = PRIOR ID; 表3

STR_LEVEL	ID	PARENT_ID	LVL	IS_LEAF
+..A	1	?	1	N
+....B	2	1	2	N
+......C	3	2	3	N
+........D	4	3	4	N
+..........H	8	4	5	Y
+..........I	9	4	5	Y
+........G	7	3	4	Y
+......E	5	2	3	Y
+......F	6	2	3	Y
+..J	10	?	1	N
+....K	11	10	2	N
+......L	12	11	3	Y
+....M	13	10	2	Y

oracle 9i 查詢根節點

view plaincopy to clipboardprint?

SELECT?RPAD('+',LEVEL*2+1,'.')||STR?STR_LEVEL,ID,PARENT_ID,LEVEL?LVL??

??FROM?idb_hierarchical?I??

?START?WITH?id?=2??

CONNECT?BY?PARENT_ID?=?PRIOR?ID;??

SELECT RPAD('+',LEVEL*2+1,'.')||STR STR_LEVEL,ID,PARENT_ID,LEVEL LVLFROM idb_hierarchical ISTART WITH id =2 CONNECT BY PARENT_ID = PRIOR ID; 表4

STR_LEVEL	ID	PARENT_ID	LVL
+..B	2	1	1
+....C	3	2	2
+......D	4	3	3
+........H	8	4	4
+........I	9	4	4
+......G	7	3	3
+....E	5	2	2
+....F	6	2	2

根節點ID應該為3、5、6，即lvl為1即可

查詢根節點，只顯示根節點SQL

view plaincopy to clipboardprint?

SELECT?RPAD('+',?LEVEL?*?2?+?1,?'.')?||?STR?STR_LEVEL,??

???????ID,??

???????PARENT_ID,??

???????LEVEL?LVL,??

???????(select?b.str??

??????????from?idb_hierarchical?b??

?????????where?level?=?1??

?????????start?with?b.id?=?2??

????????connect?by?prior?b.id?=??b.parent_id??

????????)?root_str??

??FROM?idb_hierarchical?I??

?where?level?=?1??

?START?WITH?id?=?2??

CONNECT?BY?PARENT_ID?=?PRIOR?ID;??

SELECT RPAD('+', LEVEL * 2 + 1, '.') || STR STR_LEVEL,ID,PARENT_ID,LEVEL LVL,(select b.strfrom idb_hierarchical bwhere level = 1start with b.id = 2connect by prior b.id = b.parent_id) root_strFROM idb_hierarchical Iwhere level = 1START WITH id = 2 CONNECT BY PARENT_ID = PRIOR ID; 表5

STR_LEVEL	ID	PARENT_ID	LVL	ROOT_STR
+..B	2	1	1	B

標明根節點SQL

view plaincopy to clipboardprint?

SELECT?RPAD('+',?LEVEL?*?2?+?1,?'.')?||?STR?STR_LEVEL,??

???????ID,??

???????PARENT_ID,??

???????DECODE(LEVEL,?1,?'Y',?'N')?is_root,??

???????LEVEL?LVL,??

???????(select?b.str??

??????????from?idb_hierarchical?b??

?????????where?level?=?1??

?????????start?with?b.id?=?2??

????????connect?by?prior?b.id?=?b.parent_id)?root_str??

??FROM?idb_hierarchical?I??

?START?WITH?id?=?2??

CONNECT?BY?PARENT_ID?=?PRIOR?ID;??

SELECT RPAD('+', LEVEL * 2 + 1, '.') || STR STR_LEVEL,ID,PARENT_ID,DECODE(LEVEL, 1, 'Y', 'N') is_root,LEVEL LVL,(select b.strfrom idb_hierarchical bwhere level = 1start with b.id = 2connect by prior b.id = b.parent_id) root_strFROM idb_hierarchical ISTART WITH id = 2 CONNECT BY PARENT_ID = PRIOR ID; 表6

STR_LEVEL	ID	PARENT_ID	IS_ROOT	LVL	ROOT_STR
+..B	2	1	Y	1	B
+....C	3	2	N	2	B
+......D	4	3	N	3	B
+........H	8	4	N	4	B
+........I	9	4	N	4	B
+......G	7	3	N	3	B
+....E	5	2	N	2	B
+....F	6	2	N	2	B

在oracle 10g提供了connect_by_isleaf和connect_by_root

oracle 10g用connect_by_isleaf判斷葉節點

view plaincopy to clipboardprint?

SELECT?RPAD('+',LEVEL*2+1,'.')||STR?STR_LEVEL,ID,PARENT_ID,LEVEL?LVL??

??FROM?idb_hierarchical?I??

where?connect_by_isleaf=1??

?START?WITH?PARENT_ID?IS?NULL??

CONNECT?BY?PARENT_ID?=?PRIOR?ID;??

SELECT RPAD('+',LEVEL*2+1,'.')||STR STR_LEVEL,ID,PARENT_ID,LEVEL LVLFROM idb_hierarchical I where connect_by_isleaf=1START WITH PARENT_ID IS NULL CONNECT BY PARENT_ID = PRIOR ID; 表7

STR_LEVEL	ID	PARENT_ID	LVL
+..........H	8	4	5
+..........I	9	4	5
+........G	7	3	4
+......E	5	2	3
+......F	6	2	3
+......L	12	11	3
+....M	13	10	2

view plaincopy to clipboardprint?

SELECT?RPAD('+',LEVEL*2+1,'.')||STR?STR_LEVEL,ID,PARENT_ID,LEVEL?LVL,??

decode(connect_by_isleaf,1,'Y','N')?IS_LEAF??

??FROM?idb_hierarchical?I??

?START?WITH?PARENT_ID?IS?NULL??

CONNECT?BY?PARENT_ID?=?PRIOR?ID;??

SELECT RPAD('+',LEVEL*2+1,'.')||STR STR_LEVEL,ID,PARENT_ID,LEVEL LVL, decode(connect_by_isleaf,1,'Y','N') IS_LEAFFROM idb_hierarchical ISTART WITH PARENT_ID IS NULL CONNECT BY PARENT_ID = PRIOR ID; 表8

STR_LEVEL	ID	PARENT_ID	LVL	IS_LEAF
+..A	1	?	1	N
+....B	2	1	2	N
+......C	3	2	3	N
+........D	4	3	4	N
+..........H	8	4	5	Y
+..........I	9	4	5	Y
+........G	7	3	4	Y
+......E	5	2	3	Y
+......F	6	2	3	Y
+..J	10	?	1	N
+....K	11	10	2	N
+......L	12	11	3	Y
+....M	13	10	2	Y

oracle 10g用connect_by_root判斷根節點

view plaincopy to clipboardprint?

SELECT?RPAD('+',?LEVEL?*?2?+?1,?'.')?||?STR?STR_LEVEL,??

???????ID,??

???????PARENT_ID,??

???????LEVEL?LVL,??

???????connect_by_root?STR?ROOT_STR??

??FROM?idb_hierarchical?I??

?START?WITH?id?=?2??

CONNECT?BY?PARENT_ID?=?PRIOR?ID;??

SELECT RPAD('+', LEVEL * 2 + 1, '.') || STR STR_LEVEL,ID,PARENT_ID,LEVEL LVL,connect_by_root STR ROOT_STRFROM idb_hierarchical ISTART WITH id = 2 CONNECT BY PARENT_ID = PRIOR ID; 表9STR_LEVELIDPARENT_IDLVLROOT_STR

+..B	2	1	1	B
+....C	3	2	2	B
+......D	4	3	3	B
+........H	8	4	4	B
+........I	9	4	4	B
+......G	7	3	3	B
+....E	5	2	2	B
+....F	6	2	2	B

view plaincopy to clipboardprint?

SELECT?RPAD('+',?LEVEL?*?2?+?1,?'.')?||?STR?STR_LEVEL,??

???????ID,??

???????PARENT_ID,??

???????DECODE(LEVEL,?1,?'Y',?'N')?is_root,??

???????LEVEL?LVL,??

???????connect_by_root?STR?ROOT_STR??

??FROM?idb_hierarchical?I??

?START?WITH?id?=?3??

CONNECT?BY?PARENT_ID?=?PRIOR?ID;??

SELECT RPAD('+', LEVEL * 2 + 1, '.') || STR STR_LEVEL,ID,PARENT_ID,DECODE(LEVEL, 1, 'Y', 'N') is_root,LEVEL LVL,connect_by_root STR ROOT_STRFROM idb_hierarchical ISTART WITH id = 3 CONNECT BY PARENT_ID = PRIOR ID; 表10STR_LEVELIDPARENT_IDIS_ROOTLVLROOT_STR

+..C	3	2	Y	1	C
+....D	4	3	N	2	C
+......H	8	4	N	3	C
+......I	9	4	N	3	C
+....G	7	3	N	2	C

view plaincopy to clipboardprint?

SELECT?RPAD('+',?LEVEL?*?2?+?1,?'.')?||?STR?STR_LEVEL,??

???????ID,??

???????PARENT_ID,??

???????DECODE(LEVEL,?1,?'Y',?'N')?is_root,??

???????LEVEL?LVL,??

???????connect_by_root?STR?ROOT_STR??

??FROM?idb_hierarchical?I??

?START?WITH?PARENT_ID?=?2??

CONNECT?BY?PARENT_ID?=?PRIOR?ID;??

SELECT RPAD('+', LEVEL * 2 + 1, '.') || STR STR_LEVEL,ID,PARENT_ID,DECODE(LEVEL, 1, 'Y', 'N') is_root,LEVEL LVL,connect_by_root STR ROOT_STRFROM idb_hierarchical ISTART WITH PARENT_ID = 2 CONNECT BY PARENT_ID = PRIOR ID; 表11STR_LEVELIDPARENT_IDIS_ROOTLVLROOT_STR

+..C	3	2	Y	1	C
+....D	4	3	N	2	C
+......H	8	4	N	3	C
+......I	9	4	N	3	C
+....G	7	3	N	2	C
+..E	5	2	Y	1	E
+..F	6	2	Y	1	F

總結

以上是生活随笔為你收集整理的oracle 层次查询判断叶子和根节点的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。