SQL: Select a list of numbers from “nothing”

Question

What is a fast/readable way to SELECT a relation from \"nothing\" that contains a list of numbers. I want to define which numbers by setting a start and end value. I am usi

Answer 1

A simple way to do this in PostgreSQL and SQLite is as follows:

sqlite> select 1 union select 2 union select 3;
1
2
3

It should work in most RDBMS systems, but IIRC in Oracle you would have to use:

select 1 from dual union select 2 from dual union select 3 from dual;

But I don't have an Oracle DB to test it on.

Answer 2

Some other alternative (tried in postgres, but should be working with others)

select (0) as count union values (1),(2),(3),(4),(5)

Extending this sql with code will be straight forward.

Answer 3

Well in SQL server (and PostgreSQL) I would use recursive common table expression: SQL Server, PostgreSQL

with recursive Numbers as (
    select 0 as Number
    union all
    select Number + 1
    from Numbers
    where Number < 4
)
select Number
from Numbers

SQL FIDDLE EXAMPLE

But, as far as I know, there's no WITH in SQLite.

So, the possible solutions could be

• create a user defined function (this could be helpful)

• create a table with numbers from 0 to max number you'll ever need, and then just select from it like this:

  select Number from Numbers where Number >= 0 and Number <= 4
  

Answer 4

Thanks for all answers! Following the discussion I realized that using a numbers table is not too complicated and works well and fast on both/many platforms:

CREATE TABLE integers (i integer);
INSERT INTO integers (i) VALUES (0);
INSERT INTO integers (i) VALUES (1);
...
INSERT INTO integers (i) VALUES (9);
SELECT (hundreds.i * 100) + (tens.i * 10) + units.i AS x
FROM integers AS units
  CROSS JOIN integers AS tens
  CROSS JOIN integers AS hundreds

You just create this table once and can use it whenever you need a range of numbers.