Using the HAVING clause with inner join : Having « Select Query « PostgreSQL






Using the HAVING clause with inner join

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=# 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=#
postgres=#
postgres=# -- Using the HAVING clause
postgres=#
postgres=# SELECT count(e.isbn) AS "number of books",
postgres-#         p.name AS publisher
postgres-#         FROM editions AS e INNER JOIN publishers AS p
postgres-#              ON (e.publisher_id = p.id)
postgres-#         GROUP BY publisher
postgres-#         HAVING count(e.isbn) > 1;
 number of books | publisher
-----------------+-----------
               2 | D Inc
               2 | A Inc
               2 | Z Inc
               3 | R Inc
(4 rows)

postgres=#
postgres=# drop table publishers cascade;
DROP TABLE
postgres=# drop table editions cascade;
DROP TABLE
postgres=#

           
       








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