How to generate a range of numbers between two numbers?

Question

I have two numbers as input from the user, like for example 1000 and 1050.

How do I generate the numbers between these two numbers, using

Answer 1

This uses procedural code and a table-valued function. Slow, but easy and predictable.

CREATE FUNCTION [dbo].[Sequence] (@start int, @end int)
RETURNS
@Result TABLE(ID int)
AS
begin
declare @i int;
set @i = @start;
while @i <= @end 
    begin
        insert into @result values (@i);
        set @i = @i+1;
    end
return;
end

Usage:

SELECT * FROM dbo.Sequence (3,7);
ID
3
4
5
6
7

It's a table, so you can use it in joins with other data. I most frequently use this function as the left side of a join against a GROUP BY hour, day etc to ensure a contiguous sequence of time values.

SELECT DateAdd(hh,ID,'2018-06-20 00:00:00') as HoursInTheDay FROM dbo.Sequence (0,23) ;

HoursInTheDay
2018-06-20 00:00:00.000
2018-06-20 01:00:00.000
2018-06-20 02:00:00.000
2018-06-20 03:00:00.000
2018-06-20 04:00:00.000
(...)

Performance is uninspiring (16 seconds for a million rows) but good enough for many purposes.

SELECT count(1) FROM [dbo].[Sequence] (
   1000001
  ,2000000)
GO