Help Center/ GaussDB(DWS)/ SQL Syntax Reference/ SQL Syntax Reference (9.1.0.x)/ Functions and Operators/ Set Returning Functions/ Series Generating Functions
Updated on 2024-09-02 GMT+08:00
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Series Generating Functions

generate_series() returns a series-based set based on the specified start value (start), end value (stop), and step (step).

If step is a positive number and start is greater than stop, zero row is returned. If step is a negative number and start is less than stop, zero row is returned. If any input is NULL, zero rows are returned. If the value of step is 0, an error is reported.

generate_series(start, stop)

Description: Generates a series of values, from start to stop, the default step is 1.

Parameter type: int, bigint, or numeric

Return type: setof int, setof bigint, or setof numeric (same as the argument type)

Example:

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SELECT * FROM generate_series(2,4);
 generate_series
-----------------
               2
               3
               4
(3 rows)

SELECT * FROM generate_series(4,3);
 generate_series
-----------------
(0 rows)

SELECT * FROM generate_series(1,NULL);
 generate_series
-----------------
(0 rows)

generate_series(start, stop, step)

Description: Generates a series of values, from start to stop with a step size of step.

Parameter type: int, bigint, or numeric

Return type: setof int, setof bigint, or setof numeric (same as the argument type)

Example:

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SELECT * FROM generate_series(5,1,-2);
 generate_series
-----------------
               5
               3
               1
(3 rows)

SELECT * FROM generate_series(4,6,-5);
 generate_series
-----------------
(0 rows)

SELECT * FROM generate_series(4,3,0);
ERROR:  step size cannot equal zero

generate_series(start, stop, step interval)

Description: Generates a series of values, from start to stop with a step size of step.

Parameter type: timestamp or timestamp with time zone

Return type: setof timestamp or setof timestamp with time zone (same as argument type)

Example:

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-- this example relies on the date-plus-integer operator
SELECT current_date + s.a AS dates FROM generate_series(0,14,7) AS s(a);
   dates
------------
 2017-06-02
 2017-06-09
 2017-06-16
(3 rows)

SELECT * FROM generate_series('2008-03-01 00:00'::timestamp, '2008-03-04 12:00', '10 hours');
   generate_series   
---------------------
 2008-03-01 00:00:00
 2008-03-01 10:00:00
 2008-03-01 20:00:00
 2008-03-02 06:00:00
 2008-03-02 16:00:00
 2008-03-03 02:00:00
 2008-03-03 12:00:00
 2008-03-03 22:00:00
 2008-03-04 08:00:00
(9 rows)
Parent topic: Set Returning Functions