

PostgreSQL 8.2.9 Documentation  

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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 939.
Table 939. 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  20040205 20040212 20040219 (3 rows)