PostgreSQL/Postgre SQL/RECORD

Define and use record type

postgres=#
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=#
postgres=# select * from books;
  id  |   title    | author_id | subject_id
------+------------+-----------+------------
 7808 | Java       |      4156 |          9
 4513 | Javascript |      1866 |         15
 4267 | C#         |      2001 |         15
(3 rows)
postgres=#
postgres=# drop function extract_title(integer);
DROP FUNCTION
postgres=#
postgres=# CREATE FUNCTION "extract_title" (integer) RETURNS text AS "
postgres"#   DECLARE
postgres"#     sub_id ALIAS FOR $1;
postgres"#     text_output TEXT :="""";
postgres"#     row_data RECORD;
postgres"#   BEGIN
postgres"#     FOR row_data IN SELECT * FROM books
postgres"#     WHERE subject_id = sub_id ORDER BY title  LOOP
postgres"#       text_output := row_data.title;
postgres"#     END LOOP;
postgres"#     RETURN text_output;
postgres"#   END;
postgres"# " LANGUAGE "plpgsql";
CREATE FUNCTION
postgres=#
postgres=# select extract_title(15);
 extract_title
---------------
 Javascript
(1 row)
postgres=#
postgres=# drop table books;
DROP TABLE
postgres=#
postgres=#