Generating an arithmetic sequence

Question

I would like to generate a named table in a WITH clause which will contain this arithmetic progression:

╔══════════╗
║ mynumber ║
╠══════════╣
║        0 ║
║       30 ║
║       60 ║
║       90 ║
║      120 ║
║      150 ║
║      180 ║
║      210 ║
╚══════════╝

...based on variable p_maxnumber (here p_maxnumber = 211 for example).

Ideally it would be in a format like:

WITH sequenceTable AS
(SELECT mynumber
FROM ...),

Within the same WITH clause, I would like to use that sequence in downstream derived tables to get data and to be eventually used as a time axis for chart rendering. I have a feeling there is a way to do it using create sequence? Just trying to figure a way to create this still...

Answer 1

You can use a CONNECT BY query to generate an arbitrary sequence:

SQL> variable v_step NUMBER
SQL> variable v_maxnumber NUMBER
SQL> exec :v_step := 30; :v_maxnumber := 211;

PL/SQL procedure successfully completed

SQL> WITH sequenceTable AS (
  2     SELECT (LEVEL - 1) * :v_step myNumber
  3       FROM DUAL
  4     CONNECT BY (LEVEL - 1) * :v_step <= :v_maxnumber)
  5  SELECT * FROM sequenceTable;

  MYNUMBER
----------
         0
        30
        60
        90
       120
       150
       180
       210

8 rows selected

You can also use a pipelined function:

SQL> CREATE OR REPLACE TYPE tab_number IS TABLE OF NUMBER;
  2  /

Type created

SQL> CREATE OR REPLACE FUNCTION arithmetic_sequence (p_step NUMBER, p_maxvalue NUMBER)
  2     RETURN tab_number
  3     PIPELINED
  4  IS
  5  BEGIN
  6     FOR i IN 0..p_maxvalue/p_step LOOP
  7        PIPE ROW (i*p_step);
  8     END LOOP;
  9     RETURN;
 10  END;
 11  /

Function created

SQL> SELECT COLUMN_VALUE myNumber FROM TABLE(arithmetic_sequence(30, 211));

  MYNUMBER
----------
         0
        30
        60
        90
       120
       150
       180
       210

8 rows selected