花了一段时间才回答，但我不得不把这些都写下来测试一下！
我使用过的数据：
begin
insert into student(id, name) values (1, 'Tom');
insert into student(id, name) values (2, 'Odysseas');
insert into class(id, subject) values (1, 'Programming');
insert into class(id, subject) values (2, 'Databases');
insert into class_meeting (id, class_id, meeting_sequence) values (1, 1, 10);
insert into class_meeting (id, class_id, meeting_sequence) values (2, 1, 20);
insert into class_meeting (id, class_id, meeting_sequence) values (3, 2, 10);
insert into class_meeting (id, class_id, meeting_sequence) values (4, 2, 20);
insert into meeting_attendance (id, student_id, meeting_id, present) values (1, 1, 1, 1); -- Tom was at meeting 10 about programming
insert into meeting_attendance (id, student_id, meeting_id, present) values (2, 1, 2, 1); -- Tom was at meeting 20 about programming
insert into meeting_attendance (id, student_id, meeting_id, present) values (3, 1, 3, 0); -- Tom was NOT at meeting 10 about databases
insert into meeting_attendance (id, student_id, meeting_id, present) values (4, 1, 4, 0); -- Tom was NOT at meeting 20 about databases
insert into meeting_attendance (id, student_id, meeting_id, present) values (5, 2, 1, 0); -- Odysseas was NOT at meeting 10 about programming
insert into meeting_attendance (id, student_id, meeting_id, present) values (6, 2, 2, 1); -- Odysseas was at meeting 20 about programming
insert into meeting_attendance (id, student_id, meeting_id, present) values (7, 2, 3, 0); -- Odysseas was NOT at meeting 10 about databases
insert into meeting_attendance (id, student_id, meeting_id, present) values (8, 2, 4, 1); -- Odysseas was at meeting 20 about databases
end;
PIVOT 就目前而言，不允许以简单的方式动态列数。它只允许使用 XML 关键字进行此操作，从而生成 xmltype 列。
这里有一些优秀的文档。 http://www.oracle-base.com/articles/11g/pivot-and-unpivot-operators-11gr1.php
首先阅读这些总是值得的。
那该怎么做呢？
一旦你开始搜索，你就会发现很多关于同一件事的问题。
动态 SQL
经典报表可以将返回 sql 语句的函数体作为返回值。交互式报告不能。就目前而言，IR 是不可能的，因为它过于依赖元数据。
例如，在经典报表区域源中使用这些查询/plsql：
静态枢轴
select *
from (
select s.name as student_name, m.present present, cm.meeting_sequence||'-'|| c.subject meeting
from student s
join meeting_attendance m
on s.id = m.student_id
join class_meeting cm
on cm.id = m.meeting_id
join class c
on c.id = cm.class_id
)
pivot ( max(present) for meeting in ('10-Databases' as "10-DB", '20-Databases' as "20-DB", '10-Programming' as "10-PRM", '20-Programming' as "20-PRM") );
-- Results
STUDENT_NAME '10-Databases' 20-DB 10-PRM 20-PRM
Tom 0 0 1 1
Odysseas 0 1 0 1
函数体返回语句
DECLARE
l_pivot_cols VARCHAR2(4000);
l_pivot_qry VARCHAR2(4000);
BEGIN
SELECT ''''||listagg(cm.meeting_sequence||'-'||c.subject, ''',''') within group(order by 1)||''''
INTO l_pivot_cols
FROM class_meeting cm
JOIN "CLASS" c
ON c.id = cm.class_id;
l_pivot_qry :=
'select * from ( '
|| 'select s.name as student_name, m.present present, cm.meeting_sequence||''-''||c.subject meeting '
|| 'from student s '
|| 'join meeting_attendance m '
|| 'on s.id = m.student_id '
|| 'join class_meeting cm '
|| 'on cm.id = m.meeting_id '
|| 'join class c '
|| 'on c.id = cm.class_id '
|| ') '
|| 'pivot ( max(present) for meeting in ('||l_pivot_cols||') )' ;
RETURN l_pivot_qry;
END;
但请注意区域源中的设置。
这是标准设置。它将解析您的查询，然后将在查询中找到的列存储在报告元数据中。如果您继续使用上述 plsql 代码创建报告，您可以看到 apex 已解析查询并分配了正确的列。这种方法的问题在于元数据是静态的。报表的元数据不会在每次运行报表时刷新。
这可以很简单地通过向数据添加另一个类来证明。
begin
insert into class(id, subject) values (3, 'Watch YouTube');
insert into class_meeting (id, class_id, meeting_sequence) values (5, 3, 10);
insert into meeting_attendance (id, student_id, meeting_id, present) values (10, 1, 5, 1); -- Tom was at meeting 10 about watching youtube
end;
在不编辑报告的情况下运行页面！编辑和保存会重新生成元数据，这显然不是一种可行的方法。反正数据会变，不能每次都进去保存报表元数据。
--cleanup
begin
delete from class where id = 3;
delete from class_meeting where id = 5;
delete from meeting_attendance where id = 10;
end;
将源设置为此类型将允许您使用更动态的方法。通过将报告的设置更改为这种类型的解析，apex 将仅在其元数据中生成一定数量的列，而不会直接与实际查询相关联。只有“COL1”、“COL2”、“COL3”、...
运行报告。工作正常。现在再次插入一些数据。
begin
insert into class(id, subject) values (3, 'Watch YouTube');
insert into class_meeting (id, class_id, meeting_sequence) values (5, 3, 10);
insert into meeting_attendance (id, student_id, meeting_id, present) values (10, 1, 5, 1); -- Tom was at meeting 10 about watching youtube
end;
运行报告。工作正常。
但是，这里的问题是列名。他们并不是那么有活力，名字很丑。当然，您可以编辑列，但它们不是动态的。没有显示任何类或任何内容，您也不能可靠地将它们的标题设置为一个。这又是有道理的：元数据在那里，但它是静态的。如果您对这种方法感到满意，它可能对您有用。
但是，您可以处理此问题。在报表的“报表属性”中，可以选择“标题类型”。它们都是静态的，当然期待“PL/SQL”！在这里你可以编写一个函数体（或者只是调用一个函数），它会返回列标题！
DECLARE
l_return VARCHAR2(400);
BEGIN
SELECT listagg(cm.meeting_sequence||'-'||c.subject, ':') within group(order by 1)
INTO l_return
FROM class_meeting cm
JOIN "CLASS" c
ON c.id = cm.class_id;
RETURN l_return;
END;
第三方解决方案
使用 XML
我自己之前选择使用 XML 关键字。我使用 pivot 来确保我有所有行和列的值，然后用XMLTABLE 再次读取它，然后创建一个XMLTYPE 列，将其序列化为CLOB。
这可能有点先进，但这是我迄今为止使用过几次的技术，效果很好。它很快，前提是基础数据不是太大，而且只是一个 sql 调用，所以没有很多上下文切换。我也将它与 CUBE 数据一起使用，效果很好。
（注意：我在元素上添加的类对应于主题1中经典报告中使用的类，简单红色）
DECLARE
l_return CLOB;
BEGIN
-- Subqueries:
-- SRC
-- source data query
-- SRC_PIVOT
-- pivoted source data with XML clause to allow variable columns.
-- Mainly used for convenience because pivot fills in 'gaps' in the data.
-- an example would be that 'Odysseas' does not have a relevant record for the 'Watch Youtube' class
-- PIVOT_HTML
-- Pulls the data from the pivot xml into columns again, and collates the data
-- together with xmlelments.
-- HTML_HEADERS
-- Creates a row with just header elements based on the source data
-- HTML_SRC
-- Creates row elements with the student name and the collated data from pivot_html
-- Finally:
-- serializes the xmltype column for easier-on-the-eye markup
WITH src AS (
SELECT s.name as student_name, m.present present, cm.meeting_sequence||'-'||c.subject meeting
FROM student s
JOIN meeting_attendance m
ON s.id = m.student_id
JOIN class_meeting cm
ON cm.id = m.meeting_id
JOIN class c
ON c.id = cm.class_id
),
src_pivot AS (
SELECT student_name, meeting_xml
FROM src pivot xml(MAX(NVL(present, 0)) AS is_present_max for (meeting) IN (SELECT distinct meeting FROM src) )
),
pivot_html AS (
SELECT student_name
, xmlagg(
xmlelement("td", xmlattributes('data' as "class"), is_present_max)
ORDER BY meeting
) is_present_html
FROM src_pivot
, xmltable('PivotSet/item'
passing meeting_xml
COLUMNS "MEETING" VARCHAR2(400) PATH 'column[@name="MEETING"]'
, "IS_PRESENT_MAX" NUMBER PATH 'column[@name="IS_PRESENT_MAX"]')
GROUP BY (student_name)
),
html_headers AS (
SELECT xmlelement("tr",
xmlelement("th", xmlattributes('header' as "class"), 'Student Name')
, xmlagg(xmlelement("th", xmlattributes('header' as "class"), meeting) order by meeting)
) headers
FROM (SELECT DISTINCT meeting FROM src)
),
html_src as (
SELECT
xmlagg(
xmlelement("tr",
xmlelement("td", xmlattributes('data' as "class"), student_name)
, ah.is_present_html
)
) data
FROM pivot_html ah
)
SELECT
xmlserialize( content
xmlelement("table"
, xmlattributes('report-standard' as "class", '0' as "cellpadding", '0' as "cellspacing", '0' as "border")
, xmlelement("thead", headers )
, xmlelement("tbody", data )
)
AS CLOB INDENT SIZE = 2
)
INTO l_return
FROM html_headers, html_src ;
htp.prn(l_return);
END;
在APEX中：好吧，既然已经构建了HTML，这只能是一个PLSQL区域，它调用包函数并使用HTP.PRN打印它。
（编辑）OTN 论坛上也有这个帖子，它在很大程度上做同样的事情，但不生成标题等，而是使用顶点功能：
OTN: Matrix report
PLSQL
或者，您也可以选择走好的 ol' plsql 路线。您可以从上面的动态 sql 中获取主体，对其进行循环，并通过使用 htp.prn 调用输出一个表结构。放出标题，并放出任何你想要的东西。为获得良好效果，请在与您使用的主题相对应的元素上添加类。