PostgreSQL/Aggregate Functions/SUM
SUM for a "real" value
<source lang="sql">
postgres=# postgres=# CREATE TABLE employee ( postgres(# ID int, postgres(# name varchar(10), postgres(# salary real, postgres(# start_date date, postgres(# city varchar(10), postgres(# region char(1) postgres(# ); CREATE TABLE postgres=# postgres=# insert into employee (ID, name, salary, start_date, city, region) postgres-# values (1, "Jason", 40420, "02/01/94", "New York", "W"); INSERT 0 1 postgres=# insert into employee (ID, name, salary, start_date, city, region) postgres-# values (2, "Robert",14420, "01/02/95", "Vancouver","N"); INSERT 0 1 postgres=# insert into employee (ID, name, salary, start_date, city, region) postgres-# values (3, "Celia", 24020, "12/03/96", "Toronto", "W"); INSERT 0 1 postgres=# insert into employee (ID, name, salary, start_date, city, region) postgres-# values (4, "Linda", 40620, "11/04/97", "New York", "N"); INSERT 0 1 postgres=# insert into employee (ID, name, salary, start_date, city, region) postgres-# values (5, "David", 80026, "10/05/98", "Vancouver","W"); INSERT 0 1 postgres=# insert into employee (ID, name, salary, start_date, city, region) postgres-# values (6, "James", 70060, "09/06/99", "Toronto", "N"); INSERT 0 1 postgres=# insert into employee (ID, name, salary, start_date, city, region) postgres-# values (7, "Alison",90620, "08/07/00", "New York", "W"); INSERT 0 1 postgres=# insert into employee (ID, name, salary, start_date, city, region) postgres-# values (8, "Chris", 26020, "07/08/01", "Vancouver","N"); INSERT 0 1 postgres=# insert into employee (ID, name, salary, start_date, city, region) postgres-# values (9, "Mary", 60020, "06/09/02", "Toronto", "W"); INSERT 0 1 postgres=# postgres=# select * from employee;
id | name | salary | start_date | city | region
+--------+--------+------------+-----------+--------
1 | Jason | 40420 | 1994-02-01 | New York | W 2 | Robert | 14420 | 1995-01-02 | Vancouver | N 3 | Celia | 24020 | 1996-12-03 | Toronto | W 4 | Linda | 40620 | 1997-11-04 | New York | N 5 | David | 80026 | 1998-10-05 | Vancouver | W 6 | James | 70060 | 1999-09-06 | Toronto | N 7 | Alison | 90620 | 2000-08-07 | New York | W 8 | Chris | 26020 | 2001-07-08 | Vancouver | N 9 | Mary | 60020 | 2002-06-09 | Toronto | W
(9 rows) postgres=# postgres=# SELECT sum(salary) FROM employee;
sum
446226
(1 row) postgres=# postgres=# postgres=# drop table employee; DROP TABLE postgres=# postgres=#
</source>
Using SUM function with natural join
<source lang="sql">
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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