SQL: Order randomly when inserting objects to a table

Posted by Ekaterina on Stack Overflow See other posts from Stack Overflow or by Ekaterina
Published on 2009-10-09T11:30:22Z Indexed on 2011/01/29 15:26 UTC
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I have an UDF that selects top 6 objects from a table (with a union - code below) and inserts it into another table. (btw SQL 2005)

So I paste the UDF below and what the code does is:

  • selects objects for a specific city and add a level to those (from table Europe)
  • union that selection with a selection from the same table for objects that are from the same country and add a level to those
  • From the union, selection is made to get top 6 objects, order by level, so the objects from the same city will be first, and if there aren't any available, then objects from the same country will be returned from the selection.

And my problem is, that I want to make a random selection to get random objects from table Europe, but because I insert the result of my selection into a table, I can't use order by newid() or rand() function because they are time-dependent, so I get the following errors:

  • Invalid use of side-effecting or time-dependent operator in 'newid' within a function.
  • Invalid use of side-effecting or time-dependent operator in 'rand' within a function.

UDF:

ALTER FUNCTION [dbo].[Objects] (@id uniqueidentifier)
RETURNS @objects TABLE
( 
    ObjectId uniqueidentifier NOT NULL,
    InternalId uniqueidentifier NOT NULL
)
AS
BEGIN 
    declare @city varchar(50)
    declare @country int

    select	@city = city,
    		@country = country
    from Europe
    where internalId = @id

    insert @objects
    select @id, internalId from
    (
    	select distinct top 6 [level], internalId from
    	(
    		select top 6 1 as [level], internalId
    		from Europe N4
    		where N4.city = @city
    		and N4.internalId != @id			

    		union select top 6 2 as [level], internalId
    		from Europe N5
    		where N5.countryId = @country
    		and N5.internalId != @id			

    	) as selection_1
    	order by [level]
    ) as selection_2
    return
END

If you have fresh ideas, please share them with me.

(Just please, don't suggest to order by newid() or to add a column rand() with seed DateTime (by ms or sthg), because that won't work.)

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