PostgreSQL/Table Joins/Table Join

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Aliasing columns

   <source lang="sql">

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=# CREATE TABLE "authors" ( postgres(# "id" integer NOT NULL, postgres(# "last_name" text, postgres(# "first_name" text, postgres(# Constraint "authors_pkey" Primary Key ("id") postgres(# ); NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "authors_pkey" for table "authors" CREATE TABLE postgres=# postgres=# postgres=# insert into authors values (1111, "Martin", "Jason"); INSERT 0 1 postgres=# insert into authors values (1212, "Worsley", "Robert"); INSERT 0 1 postgres=# insert into authors values (15990, "Mathews", "John"); INSERT 0 1 postgres=# insert into authors values (25041, "Smith", "Williams"); INSERT 0 1 postgres=# insert into authors values (16, "Alcott", "May"); INSERT 0 1 postgres=# insert into authors values (4156, "King", "Stephen"); INSERT 0 1 postgres=# insert into authors values (1866, "Herbert", "Margaret"); INSERT 0 1 postgres=# insert into authors values (1644, "Hogarth", "Celia"); INSERT 0 1 postgres=# insert into authors values (2031, "Brown", "Wise"); INSERT 0 1 postgres=# insert into authors values (115, "Poe", "Allen"); INSERT 0 1 postgres=# insert into authors values (7805, "Lutz", "Mark"); INSERT 0 1 postgres=# insert into authors values (7806, "Rice", "Tom"); INSERT 0 1 postgres=# insert into authors values (1533, "Black", "Chris"); INSERT 0 1 postgres=# insert into authors values (1717, "Brite", "Linda"); INSERT 0 1 postgres=# insert into authors values (2112, "Larry", "Edward"); INSERT 0 1 postgres=# insert into authors values (2001, "Clarke", "Alison"); INSERT 0 1 postgres=# insert into authors values (1213, "Green", "Mary"); INSERT 0 1 postgres=# postgres=# select * from authors;

 id   | last_name | first_name

+-----------+------------
 1111 | Martin    | Jason
 1212 | Worsley   | Robert
15990 | Mathews   | John
25041 | Smith     | Williams
   16 | Alcott    | May
 4156 | King      | Stephen
 1866 | Herbert   | Margaret
 1644 | Hogarth   | Celia
 2031 | Brown     | Wise
  115 | Poe       | Allen
 7805 | Lutz      | Mark
 7806 | Rice      | Tom
 1533 | Black     | Chris
 1717 | Brite     | Linda
 2112 | Larry     | Edward
 2001 | Clarke    | Alison
 1213 | Green     | Mary

(17 rows) postgres=# postgres=# -- Aliasing columns postgres=# postgres=# SELECT the_book_id, title, id, last_name postgres-# FROM books AS b (the_book_id), authors postgres-# WHERE author_id = id;

the_book_id |        title         |  id   | last_name

+----------------------+-------+-----------
       7808 | Java                 |  4156 | King
       4513 | Javascript           |  1866 | Herbert
       4267 | C#                   |  2001 | Clarke
      25908 | Postgre SQL          | 15990 | Mathews
       1501 | Python               |  2031 | Brown
        190 | Java by API          |    16 | Alcott
       1234 | 2D                   | 25041 | Smith
       2038 | C                    |  1644 | Hogarth
        156 | C++                  |   115 | Poe
      41473 | Programming Python   |  7805 | Lutz
      41477 | Learning Python      |  7805 | Lutz
      41478 | Perl Cookbook        |  7806 | Rice
      41472 | Practical PostgreSQL |  1212 | Worsley

(13 rows) postgres=# postgres=# postgres=# postgres=# drop table authors; DROP TABLE postgres=# drop table books; DROP TABLE postgres=# postgres=#

      </source>
   
  


Aliasing FROM sources

   <source lang="sql">

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=# CREATE TABLE "authors" ( postgres(# "id" integer NOT NULL, postgres(# "last_name" text, postgres(# "first_name" text, postgres(# Constraint "authors_pkey" Primary Key ("id") postgres(# ); NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "authors_pkey" for table "authors" CREATE TABLE postgres=# postgres=# postgres=# insert into authors values (1111, "Martin", "Jason"); INSERT 0 1 postgres=# insert into authors values (1212, "Worsley", "Robert"); INSERT 0 1 postgres=# insert into authors values (15990, "Mathews", "John"); INSERT 0 1 postgres=# insert into authors values (25041, "Smith", "Williams"); INSERT 0 1 postgres=# insert into authors values (16, "Alcott", "May"); INSERT 0 1 postgres=# insert into authors values (4156, "King", "Stephen"); INSERT 0 1 postgres=# insert into authors values (1866, "Herbert", "Margaret"); INSERT 0 1 postgres=# insert into authors values (1644, "Hogarth", "Celia"); INSERT 0 1 postgres=# insert into authors values (2031, "Brown", "Wise"); INSERT 0 1 postgres=# insert into authors values (115, "Poe", "Allen"); INSERT 0 1 postgres=# insert into authors values (7805, "Lutz", "Mark"); INSERT 0 1 postgres=# insert into authors values (7806, "Rice", "Tom"); INSERT 0 1 postgres=# insert into authors values (1533, "Black", "Chris"); INSERT 0 1 postgres=# insert into authors values (1717, "Brite", "Linda"); INSERT 0 1 postgres=# insert into authors values (2112, "Larry", "Edward"); INSERT 0 1 postgres=# insert into authors values (2001, "Clarke", "Alison"); INSERT 0 1 postgres=# insert into authors values (1213, "Green", "Mary"); INSERT 0 1 postgres=# postgres=# select * from authors;

 id   | last_name | first_name

+-----------+------------
 1111 | Martin    | Jason
 1212 | Worsley   | Robert
15990 | Mathews   | John
25041 | Smith     | Williams
   16 | Alcott    | May
 4156 | King      | Stephen
 1866 | Herbert   | Margaret
 1644 | Hogarth   | Celia
 2031 | Brown     | Wise
  115 | Poe       | Allen
 7805 | Lutz      | Mark
 7806 | Rice      | Tom
 1533 | Black     | Chris
 1717 | Brite     | Linda
 2112 | Larry     | Edward
 2001 | Clarke    | Alison
 1213 | Green     | Mary

(17 rows) postgres=# postgres=# -- Aliasing FROM sources postgres=# postgres=# SELECT b.id, title, a.id, last_name postgres-# FROM books AS b, authors AS a postgres-# WHERE b.author_id = a.id;

 id   |        title         |  id   | last_name

+----------------------+-------+-----------
 7808 | Java                 |  4156 | King
 4513 | Javascript           |  1866 | Herbert
 4267 | C#                   |  2001 | Clarke
25908 | Postgre SQL          | 15990 | Mathews
 1501 | Python               |  2031 | Brown
  190 | Java by API          |    16 | Alcott
 1234 | 2D                   | 25041 | Smith
 2038 | C                    |  1644 | Hogarth
  156 | C++                  |   115 | Poe
41473 | Programming Python   |  7805 | Lutz
41477 | Learning Python      |  7805 | Lutz
41478 | Perl Cookbook        |  7806 | Rice
41472 | Practical PostgreSQL |  1212 | Worsley

(13 rows) postgres=# postgres=# postgres=# postgres=# drop table authors; DROP TABLE postgres=# drop table books; DROP TABLE postgres=# postgres=#

      </source>
   
  


Join three tables together

   <source lang="sql">

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(# ); 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=# postgres=# CREATE TABLE "publishers" ( postgres(# "id" integer NOT NULL, postgres(# "name" text, postgres(# "address" text, postgres(# Constraint "publishers_pkey" Primary Key ("id") postgres(# ); postgres=# postgres=# postgres=# insert into publishers values(150, "Can Press", "29 Ave. Toronto, ON"); postgres=# insert into publishers values(91, "Henry Inc.", "115 Street New York, NY"); postgres=# insert into publishers values(113, "O Inc.", "101 St, Sebastopol, CA"); postgres=# insert into publishers values(62, "W Pubs", "1515, New York"); postgres=# insert into publishers values(105, "N Press", "19 W, New York"); postgres=# insert into publishers values(99, "A Inc", "375 St, New York"); postgres=# insert into publishers values(101, "Z Inc", "375 Ave, New York"); postgres=# insert into publishers values(163, "M Press", "PO Box 1215"); postgres=# insert into publishers values(171, "B", "16 W. 18th St. New York"); postgres=# insert into publishers values(102, "P Inc", "375 Hudson St, New York"); postgres=# insert into publishers values(75, "D Inc", "1540 Broadway, New York"); postgres=# insert into publishers values(65, "H Pubs", "10 E 53rd St, New York"); postgres=# insert into publishers values(59, "R Inc", "1540 Broadway, New York"); postgres=# postgres=# select * from publishers;

id  |    name    |         address

+------------+-------------------------
150 | Can Press  | 29 Ave. Toronto, ON
 91 | Henry Inc. | 115 Street New York, NY
113 | O Inc.     | 101 St, Sebastopol, CA
 62 | W Pubs     | 1515, New York
105 | N Press    | 19 W, New York
 99 | A Inc      | 375 St, New York
101 | Z Inc      | 375 Ave, New York
163 | M Press    | PO Box 1215
171 | B          | 16 W. 18th St. New York
102 | P Inc      | 375 Hudson St, New York
 75 | D Inc      | 1540 Broadway, New York
 65 | H Pubs     | 10 E 53rd St, New York
 59 | R Inc      | 1540 Broadway, New York

(13 rows) postgres=# 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=# postgres=# postgres=# SELECT avg(cost) AS average_cost, p.name AS publisher postgres-# FROM (stock JOIN editions USING (isbn)) postgres-# JOIN publishers AS p (publisher_id) postgres-# USING (publisher_id) postgres-# GROUP BY p.name;

   average_cost     | publisher

+------------
19.0000000000000000 | B
26.5000000000000000 | D Inc
26.5000000000000000 | A Inc
25.0000000000000000 | H Pubs
26.0000000000000000 | W Pubs
20.0000000000000000 | P Inc
26.5000000000000000 | Z Inc
23.0000000000000000 | Can Press
23.0000000000000000 | R Inc
23.0000000000000000 | M Press
18.0000000000000000 | Henry Inc.

(11 rows) postgres=# postgres=# drop table publishers; DROP TABLE postgres=# drop table editions; DROP TABLE postgres=#

      </source>
   
  


Join two tables with order by and group by

   <source lang="sql">

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(# ); 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=# postgres=# CREATE TABLE "publishers" ( postgres(# "id" integer NOT NULL, postgres(# "name" text, postgres(# "address" text, postgres(# Constraint "publishers_pkey" Primary Key ("id") postgres(# ); NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "publishers_pkey" for table "publishers" CREATE TABLE postgres=# postgres=# postgres=# insert into publishers values(150, "Can Press", "29 Ave. Toronto, ON"); INSERT 0 1 postgres=# insert into publishers values(91, "Henry Inc.", "115 Street New York, NY"); INSERT 0 1 postgres=# insert into publishers values(113, "O Inc.", "101 St, Sebastopol, CA"); INSERT 0 1 postgres=# insert into publishers values(62, "W Pubs", "1515, New York"); INSERT 0 1 postgres=# insert into publishers values(105, "N Press", "19 W, New York"); INSERT 0 1 postgres=# insert into publishers values(99, "A Inc", "375 St, New York"); INSERT 0 1 postgres=# insert into publishers values(101, "Z Inc", "375 Ave, New York"); INSERT 0 1 postgres=# insert into publishers values(163, "M Press", "PO Box 1215"); INSERT 0 1 postgres=# insert into publishers values(171, "B", "16 W. 18th St. New York"); INSERT 0 1 postgres=# insert into publishers values(102, "P Inc", "375 Hudson St, New York"); INSERT 0 1 postgres=# insert into publishers values(75, "D Inc", "1540 Broadway, New York"); INSERT 0 1 postgres=# insert into publishers values(65, "H Pubs", "10 E 53rd St, New York"); INSERT 0 1 postgres=# insert into publishers values(59, "R Inc", "1540 Broadway, New York"); INSERT 0 1 postgres=# postgres=# select * from publishers;

id  |    name    |         address

+------------+-------------------------
150 | Can Press  | 29 Ave. Toronto, ON
 91 | Henry Inc. | 115 Street New York, NY
113 | O Inc.     | 101 St, Sebastopol, CA
 62 | W Pubs     | 1515, New York
105 | N Press    | 19 W, New York
 99 | A Inc      | 375 St, New York
101 | Z Inc      | 375 Ave, New York
163 | M Press    | PO Box 1215
171 | B          | 16 W. 18th St. New York
102 | P Inc      | 375 Hudson St, New York
 75 | D Inc      | 1540 Broadway, New York
 65 | H Pubs     | 10 E 53rd St, New York
 59 | R Inc      | 1540 Broadway, New York

(13 rows) postgres=# postgres=# SELECT count(book_id), p.name postgres-# FROM editions JOIN publishers AS p (publisher_id) postgres-# USING (publisher_id) postgres-# GROUP BY p.name postgres-# ORDER BY count DESC;

count |    name

+------------
    3 | R Inc
    2 | Z Inc
    2 | A Inc
    2 | D Inc
    1 | W Pubs
    1 | P Inc
    1 | H Pubs
    1 | O Inc.
    1 | Can Press
    1 | B
    1 | M Press
    1 | Henry Inc.

(12 rows) postgres=# postgres=# drop table editions; DROP TABLE postgres=# drop table publishers; DROP TABLE postgres=#

      </source>
   
  


Selecting from multiple table sources

   <source lang="sql">

postgres=# postgres=# postgres=# postgres=# 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=# CREATE TABLE "authors" ( postgres(# "id" integer NOT NULL, postgres(# "last_name" text, postgres(# "first_name" text, postgres(# Constraint "authors_pkey" Primary Key ("id") postgres(# ); NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "authors_pkey" for table "authors" CREATE TABLE postgres=# postgres=# postgres=# insert into authors values (1111, "Martin", "Jason"); INSERT 0 1 postgres=# insert into authors values (1212, "Worsley", "Robert"); INSERT 0 1 postgres=# insert into authors values (15990, "Mathews", "John"); INSERT 0 1 postgres=# insert into authors values (25041, "Smith", "Williams"); INSERT 0 1 postgres=# insert into authors values (16, "Alcott", "May"); INSERT 0 1 postgres=# insert into authors values (4156, "King", "Stephen"); INSERT 0 1 postgres=# insert into authors values (1866, "Herbert", "Margaret"); INSERT 0 1 postgres=# insert into authors values (1644, "Hogarth", "Celia"); INSERT 0 1 postgres=# insert into authors values (2031, "Brown", "Wise"); INSERT 0 1 postgres=# insert into authors values (115, "Poe", "Allen"); INSERT 0 1 postgres=# insert into authors values (7805, "Lutz", "Mark"); INSERT 0 1 postgres=# insert into authors values (7806, "Rice", "Tom"); INSERT 0 1 postgres=# insert into authors values (1533, "Black", "Chris"); INSERT 0 1 postgres=# insert into authors values (1717, "Brite", "Linda"); INSERT 0 1 postgres=# insert into authors values (2112, "Larry", "Edward"); INSERT 0 1 postgres=# insert into authors values (2001, "Clarke", "Alison"); INSERT 0 1 postgres=# insert into authors values (1213, "Green", "Mary"); INSERT 0 1 postgres=# postgres=# select * from authors;

 id   | last_name | first_name

+-----------+------------
 1111 | Martin    | Jason
 1212 | Worsley   | Robert
15990 | Mathews   | John
25041 | Smith     | Williams
   16 | Alcott    | May
 4156 | King      | Stephen
 1866 | Herbert   | Margaret
 1644 | Hogarth   | Celia
 2031 | Brown     | Wise
  115 | Poe       | Allen
 7805 | Lutz      | Mark
 7806 | Rice      | Tom
 1533 | Black     | Chris
 1717 | Brite     | Linda
 2112 | Larry     | Edward
 2001 | Clarke    | Alison
 1213 | Green     | Mary

(17 rows) postgres=# postgres=# -- Selecting from multiple table sources postgres=# postgres=# SELECT books.id, title, authors.id, last_name postgres-# FROM books, authors postgres-# WHERE books.author_id = authors.id;

 id   |        title         |  id   | last_name

+----------------------+-------+-----------
 7808 | Java                 |  4156 | King
 4513 | Javascript           |  1866 | Herbert
 4267 | C#                   |  2001 | Clarke
25908 | Postgre SQL          | 15990 | Mathews
 1501 | Python               |  2031 | Brown
  190 | Java by API          |    16 | Alcott
 1234 | 2D                   | 25041 | Smith
 2038 | C                    |  1644 | Hogarth
  156 | C++                  |   115 | Poe
41473 | Programming Python   |  7805 | Lutz
41477 | Learning Python      |  7805 | Lutz
41478 | Perl Cookbook        |  7806 | Rice
41472 | Practical PostgreSQL |  1212 | Worsley

(13 rows) postgres=# postgres=# postgres=# postgres=# drop table authors; DROP TABLE postgres=# drop table books; DROP TABLE

      </source>