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PostgreSQL Reference Manual - Volume 1 - SQL Language Reference
by The PostgreSQL Global Development Group
Paperback (6"x9"), 716 pages
ISBN 0954612027
RRP £32.00 ($49.95)

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7.18 Set Returning Functions

This section describes functions that possibly return more than one row. Currently the only functions in this class are series generating functions, as detailed in Table 7-39.

Table 7-39: Series Generating Functions
Function Argument Type Return Type Description
generate_series(start, stop) int or bigint setof int or setof bigint (same as argument type) Generate a series of values, from start to stop with a step size of one
generate_series(start, stop, step) int or bigint setof int or setof bigint (same as argument type) Generate a series of values, from start to stop with a step size of step

When step is positive, zero rows are returned if start is greater than stop. Conversely, when step is negative, zero rows are returned if start is less than stop. Zero rows are also returned for NULL inputs. It is an error for step to be zero. Some examples follow:

select * from generate_series(2,4);
 generate_series
-----------------
               2
               3
               4
(3 rows)

select * from generate_series(5,1,-2);
 generate_series
-----------------
               5
               3
               1
(3 rows)

select * from generate_series(4,3);
 generate_series
-----------------
(0 rows)

select current_date + s.a as dates from generate_series(0,14,7)
 as s(a);
   dates
------------
 2004-02-05
 2004-02-12
 2004-02-19
(3 rows)
ISBN 0954612027PostgreSQL Reference Manual - Volume 1 - SQL Language ReferenceSee the print edition