Using SUM function with natural join : SUM « Aggregate Functions « PostgreSQL






Using SUM function with natural join


postgres=#
postgres=# CREATE TABLE "stock" (
postgres(#      "isbn" text NOT NULL,
postgres(#      "cost" numeric(5,2),
postgres(#      "retail" numeric(5,2),
postgres(#      "stock" integer,
postgres(#      Constraint "stock_pkey" Primary Key ("isbn")
postgres(# );
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "stock_pkey" for table "stock"
CREATE TABLE
postgres=#
postgres=#
postgres=# insert into stock values ('0385121679', 29.00, 36.95, 65);
INSERT 0 1
postgres=# insert into stock values ('039480001X', 30.00, 32.95, 31);
INSERT 0 1
postgres=# insert into stock values ('0394900014', 23.00, 23.95, 0);
INSERT 0 1
postgres=# insert into stock values ('044100590X', 36.00, 45.95, 89);
INSERT 0 1
postgres=# insert into stock values ('0441172717', 17.00, 21.95, 77);
INSERT 0 1
postgres=# insert into stock values ('0451160916', 24.00, 28.95, 22);
INSERT 0 1
postgres=# insert into stock values ('0451198492', 36.00, 46.95, 0);
INSERT 0 1
postgres=# insert into stock values ('0451457994', 17.00, 22.95, 0);
INSERT 0 1
postgres=# insert into stock values ('0590445065', 23.00, 23.95, 10);
INSERT 0 1
postgres=# insert into stock values ('0679803335', 20.00, 24.95, 18);
INSERT 0 1
postgres=# insert into stock values ('0694003611', 25.00, 28.95, 50);
INSERT 0 1
postgres=# insert into stock values ('0760720002', 18.00, 23.95, 28);
INSERT 0 1
postgres=# insert into stock values ('0823015505', 26.00, 28.95, 16);
INSERT 0 1
postgres=# insert into stock values ('0929605942', 19.00, 21.95, 25);
INSERT 0 1
postgres=# insert into stock values ('1885418035', 23.00, 24.95, 77);
INSERT 0 1
postgres=# insert into stock values ('0394800753', 16.00, 16.95, 4);
INSERT 0 1
postgres=#
postgres=# select * FROM stock;
    isbn    | cost  | retail | stock
------------+-------+--------+-------
 0385121679 | 29.00 |  36.95 |    65
 039480001X | 30.00 |  32.95 |    31
 0394900014 | 23.00 |  23.95 |     0
 044100590X | 36.00 |  45.95 |    89
 0441172717 | 17.00 |  21.95 |    77
 0451160916 | 24.00 |  28.95 |    22
 0451198492 | 36.00 |  46.95 |     0
 0451457994 | 17.00 |  22.95 |     0
 0590445065 | 23.00 |  23.95 |    10
 0679803335 | 20.00 |  24.95 |    18
 0694003611 | 25.00 |  28.95 |    50
 0760720002 | 18.00 |  23.95 |    28
 0823015505 | 26.00 |  28.95 |    16
 0929605942 | 19.00 |  21.95 |    25
 1885418035 | 23.00 |  24.95 |    77
 0394800753 | 16.00 |  16.95 |     4
(16 rows)

postgres=#
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=# 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 "editions" (
postgres(#      "isbn" text NOT NULL,
postgres(#      "book_id" integer,
postgres(#      "edition" integer,
postgres(#      "publisher_id" integer,
postgres(#      "publication" date,
postgres(#      "type" character(1),
postgres(#      CONSTRAINT "integrity" CHECK (((book_id NOTNULL) AND (edition NOTNULL))),
postgres(#      Constraint "pkey" Primary Key ("isbn")
postgres(# );
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "pkey" for table "editions"
CREATE TABLE
postgres=#
postgres=# insert into editions values('039480001X', 1608,  1,  59,  '1957-03-01', 'h');
INSERT 0 1
postgres=# insert into editions values('0451160916', 7808,  1,  75,  '1981-08-01', 'p');
INSERT 0 1
postgres=# insert into editions values('0394800753', 1590,  1,  59,  '1949-03-01', 'p');
INSERT 0 1
postgres=# insert into editions values('0590445065', 25908, 1,  150, '1987-03-01', 'p');
INSERT 0 1
postgres=# insert into editions values('0694003611', 1501,  1,  65,  '1947-03-04', 'p');
INSERT 0 1
postgres=# insert into editions values('0679803335', 1234,  1,  102, '1922-01-01', 'p');
INSERT 0 1
postgres=# insert into editions values('0760720002', 190,   1,  91,  '1868-01-01', 'p');
INSERT 0 1
postgres=# insert into editions values('0394900014', 1608,  1,  59,  '1957-01-01', 'p');
INSERT 0 1
postgres=# insert into editions values('0385121679', 7808,  2,  75,  '1993-10-01', 'h');
INSERT 0 1
postgres=# insert into editions values('1885418035', 156,   1,  163, '1995-03-28', 'p');
INSERT 0 1
postgres=# insert into editions values('0929605942', 156,   2,  171, '1998-12-01', 'p');
INSERT 0 1
postgres=# insert into editions values('0441172717', 4513,  2,  99,  '1998-09-01', 'p');
INSERT 0 1
postgres=# insert into editions values('044100590X', 4513,  3,  99,  '1999-10-01', 'h');
INSERT 0 1
postgres=# insert into editions values('0451457994', 4267,  3,  101, '2000-09-12', 'p');
INSERT 0 1
postgres=# insert into editions values('0451198492', 4267,  3,  101, '1999-10-01', 'h');
INSERT 0 1
postgres=# insert into editions values('0823015505', 2038,  1,  62,  '1958-01-01', 'p');
INSERT 0 1
postgres=# insert into editions values('0596000855', 41473, 2,  113, '2001-03-01', 'p');
INSERT 0 1
postgres=#
postgres=# select * from editions;
    isbn    | book_id | edition | publisher_id | publication | type
------------+---------+---------+--------------+-------------+------
 039480001X |    1608 |       1 |           59 | 1957-03-01  | h
 0451160916 |    7808 |       1 |           75 | 1981-08-01  | p
 0394800753 |    1590 |       1 |           59 | 1949-03-01  | p
 0590445065 |   25908 |       1 |          150 | 1987-03-01  | p
 0694003611 |    1501 |       1 |           65 | 1947-03-04  | p
 0679803335 |    1234 |       1 |          102 | 1922-01-01  | p
 0760720002 |     190 |       1 |           91 | 1868-01-01  | p
 0394900014 |    1608 |       1 |           59 | 1957-01-01  | p
 0385121679 |    7808 |       2 |           75 | 1993-10-01  | h
 1885418035 |     156 |       1 |          163 | 1995-03-28  | p
 0929605942 |     156 |       2 |          171 | 1998-12-01  | p
 0441172717 |    4513 |       2 |           99 | 1998-09-01  | p
 044100590X |    4513 |       3 |           99 | 1999-10-01  | h
 0451457994 |    4267 |       3 |          101 | 2000-09-12  | p
 0451198492 |    4267 |       3 |          101 | 1999-10-01  | h
 0823015505 |    2038 |       1 |           62 | 1958-01-01  | p
 0596000855 |   41473 |       2 |          113 | 2001-03-01  | p
(17 rows)

postgres=#
postgres=# CREATE TABLE "subjects" (
postgres(#      "id" integer NOT NULL,
postgres(#      "subject" text,
postgres(#      "location" text,
postgres(#      Constraint "subjects_pkey" Primary Key ("id")
postgres(# );
ERROR:  relation "subjects" already exists
postgres=#
postgres=# insert into subjects values (0,  'Arts', 'Creativity St');
postgres=# insert into subjects values (1,  'Business', 'Productivity Ave');
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=# SELECT sum(stock), s.subject
postgres-#         FROM ((stock NATURAL JOIN editions)
postgres(#         JOIN books ON (books.id = book_id))
postgres-#         JOIN subjects AS s
postgres-#                       ON (books.subject_id = s.id)
postgres-#         GROUP BY s.subject
postgres-#         ORDER BY sum DESC;
 sum |     subject
-----+-----------------
 189 | Horror
 166 | Science Fiction
  95 | Children
  28 | Drama
  18 | Classics
  16 | Arts
(6 rows)

postgres=#
postgres=# drop table editions;
DROP TABLE
postgres=# drop table books;
DROP TABLE
postgres=# drop table stock;
DROP TABLE
postgres=#
           
       








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