您可以使用 Oracle 的 XMLQuery 功能一次性生成 XML。为了说明这一点，我首先通过创建四个表来模拟您的设置：
SQL> create table member (id,name)
2 as
3 select 1, 'Asia Pacific Institute Of Management' from dual union all
4 select 2, 'University of Delhi' from dual union all
5 select 3, 'Acharya Narendra Dev College' from dual union all
6 select 4, 'Aditi Mahavidyalaya' from dual
7 /
Table created.
SQL> create table institute (id, member_id)
2 as
3 select 167, 1 from dual union all
4 select 182, 2 from dual union all
5 select 183, 3 from dual union all
6 select 184, 4 from dual
7 /
Table created.
SQL> create table institute_course (id,institute_id,name)
2 as
3 select 1134, 167, 'Post Graduate Diploma in Management' from dual union all
4 select 1135, 167, 'Post Graduate Diploma in Management (Marketing)' from dual union all
5 select 1136, 167, 'Post Graduate Diploma in Management (International Business)' from dual union all
6 select 1137, 167, 'Post Graduate Diploma in Management (Banking & Financial Services)' from dual union all
7 select 4283, 182, 'Bachelor of Business Studies' from dual union all
8 select 4285, 182, 'Bachelor of Commerce (Pass)' from dual union all
9 select 4291, 182, 'Bachelor of Commerce (Honours)' from dual union all
10 select 4366, 182, 'Master of Commerce' from dual union all
11 select 812, 183, 'B.Com. (Hons)' from dual union all
12 select 829, 184, 'B.Com (Pass)' from dual
13 /
Table created.
SQL> create table institute_course_category (category_id,institute_id,course_id)
2 as
3 select 47, 167, 1134 from dual union all
4 select 47, 167, 1135 from dual union all
5 select 47, 167, 1136 from dual union all
6 select 47, 167, 1137 from dual union all
7 select 47, 182, 4283 from dual union all
8 select 47, 182, 4285 from dual union all
9 select 47, 182, 4291 from dual union all
10 select 47, 182, 4366 from dual union all
11 select 47, 183, 812 from dual union all
12 select 47, 184, 829 from dual
13 /
Table created.
我创建了这四个表，以便您的查询给出与您的问题相同的结果集：
SQL> SELECT inst.*
2 FROM ( SELECT ROWNUM AS r
3 , b.name INSTNAME
4 , ICC.INSTITUTE_ID
5 , ICC.COURSE_ID
6 , c.name INSTCOURSE
7 FROM INSTITUTE_COURSE_CATEGORY ICC
8 , INSTITUTE a
9 , MEMBER b
10 , INSTITUTE_COURSE c
11 WHERE ICC.CATEGORY_ID = 47
12 AND ICC.INSTITUTE_ID = a.id
13 AND ICC.INSTITUTE_ID = c.institute_id
14 AND ICC.COURSE_ID = c.id
15 AND a.member_id = b.id
16 ) inst
17 WHERE inst.r BETWEEN 1 AND 10
18 /
R INSTNAME INSTITUTE_ID COURSE_ID INSTCOURSE
--- ------------------------------------ ------------ ---------- ------------------------------------------------------------------
1 Asia Pacific Institute Of Management 167 1137 Post Graduate Diploma in Management (Banking & Financial Services)
2 Asia Pacific Institute Of Management 167 1136 Post Graduate Diploma in Management (International Business)
3 Asia Pacific Institute Of Management 167 1135 Post Graduate Diploma in Management (Marketing)
4 Asia Pacific Institute Of Management 167 1134 Post Graduate Diploma in Management
5 University of Delhi 182 4366 Master of Commerce
6 University of Delhi 182 4291 Bachelor of Commerce (Honours)
7 University of Delhi 182 4285 Bachelor of Commerce (Pass)
8 University of Delhi 182 4283 Bachelor of Business Studies
9 Acharya Narendra Dev College 183 812 B.Com. (Hons)
10 Aditi Mahavidyalaya 184 829 B.Com (Pass)
10 rows selected.
现在 XML 查询是：
SQL> select xmlelement
2 ( "Root"
3 , xmlelement
4 ( "INSTITUTE"
5 , xmlagg(xmlforest(id,name,courses))
6 )
7 ).extract('/') your_xml
8 from ( select i.id
9 , m.name
10 , xmlagg
11 ( xmlelement
12 ( "COURSE"
13 , xmlforest(ic.id,ic.name)
14 )
15 ) courses
16 from institute i
17 inner join member m on (i.member_id = m.id)
18 inner join institute_course ic on (ic.institute_id = i.id)
19 inner join institute_course_category icc on (icc.institute_id = ic.institute_id and icc.course_id = ic.id)
20 where icc.category_id = 47
21 group by i.id
22 , m.name
23 )
24 /
YOUR_XML
--------------------------------------------------------------------------------------------------------------------------------------
<Root>
<INSTITUTE>
<ID>167</ID>
<NAME>Asia Pacific Institute Of Management</NAME>
<COURSES>
<COURSE>
<ID>1137</ID>
<NAME>Post Graduate Diploma in Management (Banking & Financial Services)</NAME>
</COURSE>
<COURSE>
<ID>1136</ID>
<NAME>Post Graduate Diploma in Management (International Business)</NAME>
</COURSE>
<COURSE>
<ID>1135</ID>
<NAME>Post Graduate Diploma in Management (Marketing)</NAME>
</COURSE>
<COURSE>
<ID>1134</ID>
<NAME>Post Graduate Diploma in Management</NAME>
</COURSE>
</COURSES>
<ID>182</ID>
<NAME>University of Delhi</NAME>
<COURSES>
<COURSE>
<ID>4366</ID>
<NAME>Master of Commerce</NAME>
</COURSE>
<COURSE>
<ID>4291</ID>
<NAME>Bachelor of Commerce (Honours)</NAME>
</COURSE>
<COURSE>
<ID>4285</ID>
<NAME>Bachelor of Commerce (Pass)</NAME>
</COURSE>
<COURSE>
<ID>4283</ID>
<NAME>Bachelor of Business Studies</NAME>
</COURSE>
</COURSES>
<ID>183</ID>
<NAME>Acharya Narendra Dev College</NAME>
<COURSES>
<COURSE>
<ID>812</ID>
<NAME>B.Com. (Hons)</NAME>
</COURSE>
</COURSES>
<ID>184</ID>
<NAME>Aditi Mahavidyalaya</NAME>
<COURSES>
<COURSE>
<ID>829</ID>
<NAME>B.Com (Pass)</NAME>
</COURSE>
</COURSES>
</INSTITUTE>
</Root>
1 row selected.
以下是使用的函数的文档：
XMLElement
XMLForest
XMLAgg
请注意，我.extract('/')仅用于漂亮的打印。你可以把它关掉。
而且，仅仅因为您当前的查询只有两个级别，您可以通过使用下面的查询来稍微缩短查询。但是，当您有两个以上的级别时，您必须使用可以轻松扩展的内联变体。
SQL> select xmlelement
2 ( "Root"
3 , xmlelement
4 ( "INSTITUTE"
5 , xmlagg
6 ( xmlforest
7 ( i.id
8 , m.name
9 , xmlagg
10 ( xmlelement
11 ( "COURSE"
12 , xmlforest(ic.id,ic.name)
13 )
14 ) as "COURSES"
15 )
16 )
17 )
18 ).extract('/') your_xml
19 from institute i
20 inner join member m on (i.member_id = m.id)
21 inner join institute_course ic on (ic.institute_id = i.id)
22 inner join institute_course_category icc on (icc.institute_id = ic.institute_id and icc.course_id = ic.id)
23 where icc.category_id = 47
24 group by i.id
25 , m.name
26 /
希望这可以帮助。
问候，
罗布。