generate days from date range

Question

I would like to run a query like

select ... as days where `date` is between \'2010-01-20\' and \'2010-01-24\'

And return data like:

Answer 1

Using a recursive Common Table Expression (CTE), you can generate a list of dates, then select from it. Obviously you normally wouldn't want to create three million dates, so this just illustrates the possibilities. You could simply limit the date range inside the CTE and omit the where clause from the select statement using the CTE.

with [dates] as (
    select convert(datetime, '1753-01-01') as [date] --start
    union all
    select dateadd(day, 1, [date])
    from [dates]
    where [date] < '9999-12-31' --end
)
select [date]
from [dates]
where [date] between '2013-01-01' and '2013-12-31'
option (maxrecursion 0)

On Microsoft SQL Server 2005, generating the CTE list of all possible dates took 1:08. Generating one hundred years took less than a second.