Using DISTINCT with ORDER BY : Order « Select Query « PostgreSQL

1. PostgreSQL
2. Select Query
3. Order

Using DISTINCT with ORDER BY

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=#
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
(6 rows)

postgres=#
postgres=# -- Using DISTINCT with ORDER BY
postgres=#
postgres=# SELECT DISTINCT ON (edition)
postgres-#         edition, publication
postgres-#         FROM editions
postgres-#         ORDER BY edition ASC,
postgres-#                  publication DESC;
 edition | publication
---------+-------------
       1 | 1987-03-01
(1 row)

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

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