Create Sequence

The CREATE SEQUENCE statement creates a new sequence number generator.

Examples

Create an ascending sequence called serial, starting at 101:

CREATE SEQUENCE serial START 101;

Select the next number from this sequence:

SELECT nextval('serial');

 nextval
---------
     101

Optionally you may also view the current number from this sequence. Note that the nextval function must have already been called before calling currval.

SELECT currval('serial');

 currval
---------
     101

Use this sequence in an INSERT command:

INSERT INTO distributors VALUES (nextval('serial'), 'nothing');

Syntax

CREATE SEQUENCE creates a new sequence number generator.

If a schema name is given then the sequence is created in the specified schema. Otherwise it is created in the current schema. Temporary sequences exist in a special schema, so a schema name may not be given when creating a temporary sequence. The sequence name must be distinct from the name of any other sequence in the same schema.

After a sequence is created, you use the function nextval to operate on the sequence.

Parameters

Name	Description
TEMPORARY or TEMP	If specified, the sequence object is created only for this session, and is automatically dropped on session exit. Existing permanent sequences with the same name are not visible (in this session) while the temporary sequence exists, unless they are referenced with schema-qualified names.
name	The name (optionally schema-qualified) of the sequence to be created.
increment	The optional clause INCREMENT BY increment specifies which value is added to the current sequence value to create a new value. A positive value will make an ascending sequence, a negative one a descending sequence. The default value is 1.
minvalue	The optional clause MINVALUE minvalue determines the minimum value a sequence can generate. If this clause is not supplied or NO MINVALUE is specified, then defaults will be used. The defaults are 1 and -(2^63 - 1) for ascending and descending sequences, respectively.
maxvalue	The optional clause MAXVALUE maxvalue determines the maximum value for the sequence. If this clause is not supplied or NO MAXVALUE is specified, then default values will be used. The defaults are 2^63 - 1 and -1 for ascending and descending sequences, respectively.
start	The optional clause START WITH start allows the sequence to begin anywhere. The default starting value is minvalue for ascending sequences and maxvalue for descending ones.
CYCLE or NO CYCLE	The CYCLE option allows the sequence to wrap around when the maxvalue or minvalue has been reached by an ascending or descending sequence respectively. If the limit is reached, the next number generated will be the minvalue or maxvalue, respectively.

If NO CYCLE is specified, any calls to nextval after the sequence has reached its maximum value will return an error. If neither CYCLE or NO CYCLE are specified, NO CYCLE is the default.

Use DROP SEQUENCE to remove a sequence. Sequences are based on BIGINT arithmetic, so the range cannot exceed the range of an eight-byte integer (-9223372036854775808 to 9223372036854775807).