Question

I have the following SQL query:

DECLARE @MyVar datetime = '1/1/2010'    
SELECT @MyVar

This naturally returns ‘1/1/2010’.

What I want to do is have a list of dates, say:

1/1/2010
2/1/2010
3/1/2010
4/1/2010
5/1/2010

Then i want to FOR EACH through the numbers and run the SQL Query.

Something like (pseudocode):

List = 1/1/2010,2/1/2010,3/1/2010,4/1/2010,5/1/2010

For each x in List
do
  DECLARE @MyVar datetime = x

  SELECT @MyVar

So this would return:-

1/1/2010
2/1/2010
3/1/2010
4/1/2010
5/1/2010

I want this to return the data as one resultset, not multiple resultsets, so I may need to use some kind of union at the end of the query, so each iteration of the loop unions onto the next.

edit

I have a large query that accepts a ‘to date’ parameter, I need to run it 24 times, each time with a specific to date which I need to be able to supply (these dates are going to be dynamic) I want to avoid repeating my query 24 times with union alls joining them as if I need to come back and add additional columns it would be very time consuming.

Answer 1

SQL is primarily a set-orientated language – it’s generally a bad idea to use a loop in it.

In this case, a similar result could be achieved using a recursive CTE:

with cte as
(select 1 i union all
 select i+1 i from cte where i < 5)
select dateadd(d, i-1, '2010-01-01') from cte