PostgreSQL/Sequence/Sequence Value

Get next sequence value

   <source lang="sql">

postgres=# -- Creation of a sequence postgres=# postgres=# CREATE SEQUENCE shipments_ship_id_seq START 200 INCREMENT 1; CREATE SEQUENCE postgres=# postgres=# -- Select the next number from a sequence with the nextval() function: postgres=# postgres=# SELECT nextval ("shipments_ship_id_seq");

nextval

---

    200

(1 row) postgres=# postgres=# postgres=# drop sequence shipments_ship_id_seq; DROP SEQUENCE postgres=#

      </source>
   
  

Get sequence last value and increment_by

   <source lang="sql">

postgres=# CREATE SEQUENCE myseq MINVALUE 0; CREATE SEQUENCE postgres=# postgres=# SELECT last_value, increment_by FROM myseq;

last_value | increment_by

---

+--------------

         0 |            1

(1 row) postgres=# postgres=# drop sequence myseq; DROP SEQUENCE postgres=#

      </source>
   
  

Get sequence next value

   <source lang="sql">

postgres=# CREATE SEQUENCE myseq MINVALUE 0; CREATE SEQUENCE postgres=# -- Incrementing a sequence postgres=# postgres=# SELECT nextval("myseq");

nextval

---

      0

(1 row) postgres=# postgres=# SELECT nextval("myseq");

nextval

---

      1

(1 row) postgres=# postgres=# drop sequence myseq; DROP SEQUENCE postgres=#

      </source>
   
  

Reference sequence value in insert statement

   <source lang="sql">

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=# -- Creation of a sequence postgres=# postgres=# CREATE SEQUENCE myseq START 200 INCREMENT 1; CREATE SEQUENCE postgres=# postgres=# INSERT INTO employee (id)VALUES (nextval("myseq")); 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
200 |        |        |            |           |

(10 rows) postgres=# postgres=# drop sequence myseq; DROP SEQUENCE postgres=# drop table employee; DROP TABLE postgres=# postgres=#

      </source>
   
  

Reference sequence value in table creation statement

   <source lang="sql">

postgres=# -- Creation of a sequence postgres=# postgres=# CREATE SEQUENCE myseq START 200 INCREMENT 1; CREATE SEQUENCE postgres=# postgres=# CREATE TABLE shipments ( postgres(# id integer NOT NULL DEFAULT nextval("myseq"), postgres(# customer_id integer, postgres(# isbn text, postgres(# ship_date timestamp); CREATE TABLE postgres=# postgres=# postgres=# drop table shipments; DROP TABLE postgres=# drop sequence myseq; DROP SEQUENCE postgres=#

      </source>