Oracle SQL：如何连接文本直到达到最大大小
Oracle SQL: how to concatenate text until reaches maximum size
我有一个案例：
一些要重现的脚本：
create table test_Txt(
id number(1),
text varchar(2000)
);
insert into test_txt values(1,'BRUG HIDDEN 4. The student is obliged to justify the absence from educational classes within the specified period:
1) parents or legal guardians excuse the student''s absence by the end of the second week of the following month / for the previous month / in justified cases (e.g. a visit to a doctor), the parent or legal guardian may exempt some classes in person or in writing;
2) in the event of a student''s resignation from participation in non-compulsory classes, written information from the parent or legal guardian is required;
3) expected absence of a student for more than one week (e.g. stay in a sanatorium, hospital, chronic disease), parents or legal guardians are obliged to notify the class teacher within 3 days;
4) if the absence is not excused within the prescribed period, the class teacher explains the reasons for the absence with the parents or legal guardians;
5) information about frequent absenteeism of students is passed to the school pedagogue, parents are called
6)xfasdfkjasdgkdsethkgjaskgjbsajgbkjsdguihifafa');
insert into test_txt values(2,'BRUG HIDDEN 4. The student is obliged to justify the absence from educational classes within the specified period:
1) parents or legal guardians excuse the student''s absence by the end of the second week of the following month / for the previous month / in justified cases (e.g. a visit to a doctor), the parent or legal guardian may exempt some classes in person or in writing;
2) in the event of a student''s resignation from participation in non-compulsory classes, written information from the parent or legal guardian is required;
3) expected absence of a student for more than one week (e.g. stay in a sanatorium, hospital, chronic disease), parents or legal guardians are obliged to notify the class teacher within 3 days;
4) if the absence is not excused within the prescribed period, the class teacher explains the reasons for the absence with the parents or legal guardians;
5) information about frequent absenteeism of students is passed to the school pedagogue, parents are called
6)xfasdfkjasdgkdsethkgjaskgjbsajgbkjsdguihifafa');
insert into test_txt values(3,'BRUG HIDDEN 4. The student is obliged to justify the absence from educational classes within the specified period:
1) parents or legal guardians excuse the student''s absence by the end of the second week of the following month / for the previous month / in justified cases (e.g. a visit to a doctor), the parent or legal guardian may exempt some classes in person or in writing;
2) in the event of a student''s resignation from participation in non-compulsory classes, written information from the parent or legal guardian is required;
3) expected absence of a student for more than one week (e.g. stay in a sanatorium, hospital, chronic disease), parents or legal guardians are obliged to notify the class teacher within 3 days;
4) if the absence is not excused within the prescribed period, the class teacher explains the reasons for the absence with the parents or legal guardians;
5) information about frequent absenteeism of students is passed to the school pedagogue, parents are called
6)xfasdfkjasdgkdsethkgjaskgjbsajgbkjsdguihifafa');
insert into test_txt values(4,'BRUG HIDDEN 4. The student is obliged to justify the absence from educational classes within the specified period:
1) parents or legal guardians excuse the student''s absence by the end of the second week of the following month / for the previous month / in justified cases (e.g. a visit to a doctor), the parent or legal guardian may exempt some classes in person or in writing;
2) in the event of a student''s resignation from participation in non-compulsory classes, written information from the parent or legal guardian is required;
3) expected absence of a student for more than one week (e.g. stay in a sanatorium, hospital, chronic disease), parents or legal guardians are obliged to notify the class teacher within 3 days;
4) if the absence is not excused within the prescribed period, the class teacher explains the reasons for the absence with the parents or legal guardians;
5) information about frequent absenteeism of students is passed to the school pedagogue, parents are called
6)xfasdfkjasdgkdsethkgjaskgjbsajgbkjsdguihifafa');
insert into test_txt values(5,'BRUG HIDDEN 4. The student is obliged to justify the absence from educational classes within the specified period:
1) parents or legal guardians excuse the student''s absence by the end of the second week of the following month / for the previous month / in justified cases (e.g. a visit to a doctor), the parent or legal guardian may exempt some classes in person or in writing;
2) in the event of a student''s resignation from participation in non-compulsory classes, written information from the parent or legal guardian is required;
3) expected absence of a student for more than one week (e.g. stay in a sanatorium, hospital, chronic disease), parents or legal guardians are obliged to notify the class teacher within 3 days;
4) if the absence is not excused within the prescribed period, the class teacher explains the reasons for the absence with the parents or legal guardians;
5) information about frequent absenteeism of students is passed to the school pedagogue, parents are called
6)xfasdfkjasdgkdsethkgjaskgjbsajgbkjsdguihifafa');
insert into test_txt values(6,'BRUG HIDDEN 4. The student is obliged to justify the absence from educational classes within the specified period:
1) parents or legal guardians excuse the student''s absence by the end of the second week of the following month / for the previous month / in justified cases (e.g. a visit to a doctor), the parent or legal guardian may exempt some classes in person or in writing;
2) in the event of a student''s resignation from participation in non-compulsory classes, written information from the parent or legal guardian is required;
3) expected absence of a student for more than one week (e.g. stay in a sanatorium, hospital, chronic disease), parents or legal guardians are obliged to notify the class teacher within 3 days;
4) if the absence is not excused within the prescribed period, the class teacher explains the reasons for the absence with the parents or legal guardians;
5) information about frequent absenteeism of students is passed to the school pedagogue, parents are called
6)xfasdfkjasdgkdsethkgjaskgjbsajgbkjsdguihifafa');
和Select：
SELECT t.*,FLOOR((sum_text)/3000)
FROM (SELECT id,
TO_CHAR(text) AS text,
LENGTH(text) AS len_Text,
SUM(LENGTH(text)) OVER(ORDER BY id DESC RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS sum_text
FROM test_txt) t;
我想要实现的是连接文本，直到它们的总和小于 3000。如果更大，那么另一个文本。
ID LEN_TEXT SUM_TEXT FLOOR((SUM_TEXT)/3000)
6 1039 1039 0
5 1039 2078 0
4 1039 3117 1
3 1039 4156 1
2 1039 5195 1
1 1039 6234 2
问题来了：当您对第 1 组的文本求和时，它们大于 3000。id = 2 的文本应该有第 2 组，但实际上是 1。
有人有想法吗？
谢谢
从 Oracle 12 开始，您可以使用 MATCH_RECOGNIZE:
SELECT id,
LENGTH( text ) AS text_len,
match_num,
SUM( LENGTH( text ) ) OVER ( PARTITION BY match_num ) AS total_len
FROM test_txt
MATCH_RECOGNIZE(
ORDER BY id
MEASURES
MATCH_NUMBER() - 1 AS match_num
ALL ROWS PER MATCH
PATTERN ( a+ )
DEFINE
A AS SUM( LENGTH( text )) <= 3000
)
对于您的示例数据，输出：
ID
TEXT_LEN
MATCH_NUM
TOTAL_LEN
1
1039
0
2078
2
1039
0
2078
3
1039
1
2078
4
1039
1
2078
5
1039
2
2078
6
1039
2
2078
db<>fiddle here
我有一个案例：
一些要重现的脚本：
create table test_Txt(
id number(1),
text varchar(2000)
);
insert into test_txt values(1,'BRUG HIDDEN 4. The student is obliged to justify the absence from educational classes within the specified period:
1) parents or legal guardians excuse the student''s absence by the end of the second week of the following month / for the previous month / in justified cases (e.g. a visit to a doctor), the parent or legal guardian may exempt some classes in person or in writing;
2) in the event of a student''s resignation from participation in non-compulsory classes, written information from the parent or legal guardian is required;
3) expected absence of a student for more than one week (e.g. stay in a sanatorium, hospital, chronic disease), parents or legal guardians are obliged to notify the class teacher within 3 days;
4) if the absence is not excused within the prescribed period, the class teacher explains the reasons for the absence with the parents or legal guardians;
5) information about frequent absenteeism of students is passed to the school pedagogue, parents are called
6)xfasdfkjasdgkdsethkgjaskgjbsajgbkjsdguihifafa');
insert into test_txt values(2,'BRUG HIDDEN 4. The student is obliged to justify the absence from educational classes within the specified period:
1) parents or legal guardians excuse the student''s absence by the end of the second week of the following month / for the previous month / in justified cases (e.g. a visit to a doctor), the parent or legal guardian may exempt some classes in person or in writing;
2) in the event of a student''s resignation from participation in non-compulsory classes, written information from the parent or legal guardian is required;
3) expected absence of a student for more than one week (e.g. stay in a sanatorium, hospital, chronic disease), parents or legal guardians are obliged to notify the class teacher within 3 days;
4) if the absence is not excused within the prescribed period, the class teacher explains the reasons for the absence with the parents or legal guardians;
5) information about frequent absenteeism of students is passed to the school pedagogue, parents are called
6)xfasdfkjasdgkdsethkgjaskgjbsajgbkjsdguihifafa');
insert into test_txt values(3,'BRUG HIDDEN 4. The student is obliged to justify the absence from educational classes within the specified period:
1) parents or legal guardians excuse the student''s absence by the end of the second week of the following month / for the previous month / in justified cases (e.g. a visit to a doctor), the parent or legal guardian may exempt some classes in person or in writing;
2) in the event of a student''s resignation from participation in non-compulsory classes, written information from the parent or legal guardian is required;
3) expected absence of a student for more than one week (e.g. stay in a sanatorium, hospital, chronic disease), parents or legal guardians are obliged to notify the class teacher within 3 days;
4) if the absence is not excused within the prescribed period, the class teacher explains the reasons for the absence with the parents or legal guardians;
5) information about frequent absenteeism of students is passed to the school pedagogue, parents are called
6)xfasdfkjasdgkdsethkgjaskgjbsajgbkjsdguihifafa');
insert into test_txt values(4,'BRUG HIDDEN 4. The student is obliged to justify the absence from educational classes within the specified period:
1) parents or legal guardians excuse the student''s absence by the end of the second week of the following month / for the previous month / in justified cases (e.g. a visit to a doctor), the parent or legal guardian may exempt some classes in person or in writing;
2) in the event of a student''s resignation from participation in non-compulsory classes, written information from the parent or legal guardian is required;
3) expected absence of a student for more than one week (e.g. stay in a sanatorium, hospital, chronic disease), parents or legal guardians are obliged to notify the class teacher within 3 days;
4) if the absence is not excused within the prescribed period, the class teacher explains the reasons for the absence with the parents or legal guardians;
5) information about frequent absenteeism of students is passed to the school pedagogue, parents are called
6)xfasdfkjasdgkdsethkgjaskgjbsajgbkjsdguihifafa');
insert into test_txt values(5,'BRUG HIDDEN 4. The student is obliged to justify the absence from educational classes within the specified period:
1) parents or legal guardians excuse the student''s absence by the end of the second week of the following month / for the previous month / in justified cases (e.g. a visit to a doctor), the parent or legal guardian may exempt some classes in person or in writing;
2) in the event of a student''s resignation from participation in non-compulsory classes, written information from the parent or legal guardian is required;
3) expected absence of a student for more than one week (e.g. stay in a sanatorium, hospital, chronic disease), parents or legal guardians are obliged to notify the class teacher within 3 days;
4) if the absence is not excused within the prescribed period, the class teacher explains the reasons for the absence with the parents or legal guardians;
5) information about frequent absenteeism of students is passed to the school pedagogue, parents are called
6)xfasdfkjasdgkdsethkgjaskgjbsajgbkjsdguihifafa');
insert into test_txt values(6,'BRUG HIDDEN 4. The student is obliged to justify the absence from educational classes within the specified period:
1) parents or legal guardians excuse the student''s absence by the end of the second week of the following month / for the previous month / in justified cases (e.g. a visit to a doctor), the parent or legal guardian may exempt some classes in person or in writing;
2) in the event of a student''s resignation from participation in non-compulsory classes, written information from the parent or legal guardian is required;
3) expected absence of a student for more than one week (e.g. stay in a sanatorium, hospital, chronic disease), parents or legal guardians are obliged to notify the class teacher within 3 days;
4) if the absence is not excused within the prescribed period, the class teacher explains the reasons for the absence with the parents or legal guardians;
5) information about frequent absenteeism of students is passed to the school pedagogue, parents are called
6)xfasdfkjasdgkdsethkgjaskgjbsajgbkjsdguihifafa');
和Select：
SELECT t.*,FLOOR((sum_text)/3000)
FROM (SELECT id,
TO_CHAR(text) AS text,
LENGTH(text) AS len_Text,
SUM(LENGTH(text)) OVER(ORDER BY id DESC RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS sum_text
FROM test_txt) t;
我想要实现的是连接文本，直到它们的总和小于 3000。如果更大，那么另一个文本。
ID LEN_TEXT SUM_TEXT FLOOR((SUM_TEXT)/3000)
6 1039 1039 0
5 1039 2078 0
4 1039 3117 1
3 1039 4156 1
2 1039 5195 1
1 1039 6234 2
问题来了：当您对第 1 组的文本求和时，它们大于 3000。id = 2 的文本应该有第 2 组，但实际上是 1。
有人有想法吗？ 谢谢
从 Oracle 12 开始，您可以使用 MATCH_RECOGNIZE:
SELECT id,
LENGTH( text ) AS text_len,
match_num,
SUM( LENGTH( text ) ) OVER ( PARTITION BY match_num ) AS total_len
FROM test_txt
MATCH_RECOGNIZE(
ORDER BY id
MEASURES
MATCH_NUMBER() - 1 AS match_num
ALL ROWS PER MATCH
PATTERN ( a+ )
DEFINE
A AS SUM( LENGTH( text )) <= 3000
)
对于您的示例数据，输出：
ID TEXT_LEN MATCH_NUM TOTAL_LEN 1 1039 0 2078 2 1039 0 2078 3 1039 1 2078 4 1039 1 2078 5 1039 2 2078 6 1039 2 2078
db<>fiddle here