Mega Code Archive

Nested for loop

postgres=# CREATE TABLE "books" ( postgres(# "id" integer NOT NULL, postgres(# "title" text NOT NULL, postgres(# "author_id" integer, postgres(# "subject_id" integer, postgres(# Constraint "books_id_pkey" Primary Key ("id") postgres(# ); NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "books_id_pkey" for table "books" CREATE TABLE postgres=# postgres=# postgres=# insert into books values (7808, 'Java', 4156, 9); INSERT 0 1 postgres=# insert into books values (4513, 'Javascript', 1866, 15); INSERT 0 1 postgres=# insert into books values (4267, 'C#', 2001, 15); INSERT 0 1 postgres=# insert into books values (1608, 'Oracle', 1809, 2); INSERT 0 1 postgres=# insert into books values (1590, 'Sql Server', 1809, 2); INSERT 0 1 postgres=# insert into books values (25908, 'Postgre SQL', 15990, 2); INSERT 0 1 postgres=# insert into books values (1501, 'Python', 2031, 2); INSERT 0 1 postgres=# insert into books values (190, 'Java by API', 16, 6); INSERT 0 1 postgres=# insert into books values (1234, '2D', 25041, 3); INSERT 0 1 postgres=# insert into books values (2038, 'C', 1644, 0); INSERT 0 1 postgres=# insert into books values (156, 'C++', 115, 9); INSERT 0 1 postgres=# insert into books values (41473, 'Programming Python', 7805, 4); INSERT 0 1 postgres=# insert into books values (41477, 'Learning Python', 7805, 4); INSERT 0 1 postgres=# insert into books values (41478, 'Perl Cookbook', 7806, 4); INSERT 0 1 postgres=# insert into books values (41472, 'Practical PostgreSQL', 1212, 4); INSERT 0 1 postgres=# postgres=# select * from books; id | title | author_id | subject_id -------+----------------------+-----------+------------ 7808 | Java | 4156 | 9 4513 | Javascript | 1866 | 15 4267 | C# | 2001 | 15 1608 | Oracle | 1809 | 2 1590 | Sql Server | 1809 | 2 25908 | Postgre SQL | 15990 | 2 1501 | Python | 2031 | 2 190 | Java by API | 16 | 6 1234 | 2D | 25041 | 3 2038 | C | 1644 | 0 156 | C++ | 115 | 9 41473 | Programming Python | 7805 | 4 41477 | Learning Python | 7805 | 4 41478 | Perl Cookbook | 7806 | 4 41472 | Practical PostgreSQL | 1212 | 4 (15 rows) postgres=# postgres=# postgres=# CREATE TABLE "subjects" ( postgres(# "id" integer NOT NULL, postgres(# "subject" text, postgres(# "location" text, postgres(# Constraint "subjects_pkey" Primary Key ("id") postgres(# ); NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "subjects_pkey" for table "subjects" CREATE TABLE postgres=# postgres=# insert into subjects values (0, 'Arts', 'Creativity St'); INSERT 0 1 postgres=# insert into subjects values (1, 'Business', 'Productivity Ave'); INSERT 0 1 postgres=# insert into subjects values (2, 'Children', 'Books Kids Ct'); INSERT 0 1 postgres=# insert into subjects values (3, 'Classics', 'Academic Rd'); INSERT 0 1 postgres=# insert into subjects values (4, 'Computers', 'Productivity Ave'); INSERT 0 1 postgres=# insert into subjects values (5, 'Cooking', 'Creativity St'); INSERT 0 1 postgres=# insert into subjects values (6, 'Drama', 'Main St'); INSERT 0 1 postgres=# insert into subjects values (7, 'Entertainment', 'Main St'); INSERT 0 1 postgres=# insert into subjects values (8, 'History', 'Academic Rd'); INSERT 0 1 postgres=# insert into subjects values (9, 'Horror', 'Black Raven Dr'); INSERT 0 1 postgres=# insert into subjects values (10, 'Mystery', 'Black Raven Dr'); INSERT 0 1 postgres=# insert into subjects values (11, 'Poetry', 'Sunset Dr'); INSERT 0 1 postgres=# insert into subjects values (12, 'Religion', 'Regina'); INSERT 0 1 postgres=# insert into subjects values (13, 'Romance', 'Main St'); INSERT 0 1 postgres=# insert into subjects values (14, 'Science', 'Productivity Ave'); INSERT 0 1 postgres=# insert into subjects values (15, 'Science Fiction', 'Main St'); INSERT 0 1 postgres=# postgres=# select * from subjects; id | subject | location ----+-----------------+------------------ 0 | Arts | Creativity St 1 | Business | Productivity Ave 2 | Children | Books Kids Ct 3 | Classics | Academic Rd 4 | Computers | Productivity Ave 5 | Cooking | Creativity St 6 | Drama | Main St 7 | Entertainment | Main St 8 | History | Academic Rd 9 | Horror | Black Raven Dr 10 | Mystery | Black Raven Dr 11 | Poetry | Sunset Dr 12 | Religion | Regina 13 | Romance | Main St 14 | Science | Productivity Ave 15 | Science Fiction | Main St (16 rows) postgres=# postgres=# postgres=# postgres=# drop function extract_all_titles2(); DROP FUNCTION postgres=# postgres=# CREATE FUNCTION "extract_all_titles2" () RETURNS text AS ' postgres'# DECLARE postgres'# sub_id INTEGER; postgres'# text_output TEXT = '' ''; postgres'# sub_title TEXT; postgres'# row_data books%ROWTYPE; postgres'# BEGIN postgres'# FOR i IN 0..15 LOOP postgres'# SELECT INTO sub_title subject FROM subjects WHERE id = i; postgres'# text_output = text_output || '''' || sub_title || '':''; postgres'# postgres'# FOR row_data IN SELECT * FROM books postgres'# WHERE subject_id = i LOOP postgres'# postgres'# text_output := text_output || row_data.title || ''''; postgres'# postgres'# END LOOP; postgres'# END LOOP; postgres'# RETURN text_output; postgres'# END; postgres'# ' LANGUAGE 'plpgsql'; CREATE FUNCTION postgres=# postgres=# select extract_all_titles2(); extract_all_titles2 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Arts:CBusiness:Children:OracleSql ServerPostgre SQLPythonClassics:2DComputers:Programming PythonLearning PythonPerl CookbookPractical PostgreSQLCooking:Drama:Java by APIEntertainment:History:Horror:JavaC++Mystery:Poetry:Religion:Romance:Science:Science Fiction:JavascriptC# (1 row) postgres=# postgres=# postgres=# drop table books; DROP TABLE postgres=# drop table subjects; DROP TABLE postgres=#