PostgreSQL/Table Joins/LEFT OUTER JOIN

Материал из SQL эксперт
Перейти к: навигация, поиск

LEFT OUTER JOIN Demo

   <source lang="sql">

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=# 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=# postgres=# postgres=# SELECT title, isbn postgres-# FROM books LEFT OUTER JOIN editions postgres-# ON (books.id = editions.book_id);

       title         |    isbn

+------------
C++                  | 0929605942
C++                  | 1885418035
Java by API          | 0760720002
2D                   | 0679803335
Python               | 0694003611
Sql Server           | 0394800753
Oracle               | 039480001X
Oracle               | 0394900014
C                    | 0823015505
C#                   | 0451457994
C#                   | 0451198492
Javascript           | 044100590X
Javascript           | 0441172717
Java                 | 0451160916
Java                 | 0385121679
Postgre SQL          | 0590445065
Practical PostgreSQL |
Programming Python   | 0596000855
Learning Python      |
Perl Cookbook        |

(20 rows) postgres=# postgres=# postgres=# drop table editions cascade; DROP TABLE postgres=# drop table books cascade; DROP TABLE postgres=# postgres=#

      </source>