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Numbers table from cross join

Author

Topic

Andrew Zwicker
Starting Member

11 Posts

Posted - 2011-05-29 : 00:36:00

I recently profiled on my site at [url]http://www.helpwithsql.com/2011/05/cartesian-join-for-numbers/[/url] a query that can be used for using cross joins to populate a numbers table. I'm reposting the sql for doing this here. This runs in ~3 seconds and currently inserts 800,000 records. This can be modified to insert fewer or more numbers as needed.

A few examples of number tables in use can be found here [scroll halfway down]: [url]http://www.sqlservercentral.com/articles/Advanced%20Querying/2547/[/url]

Here's the SQL. I used a table variable @numbers for the numbers 0-9, but if you're using SQL Server 2000, you'll need to instead use a temp table [#numbers].


create table numbers(number int)

----- Use a table variable 
DECLARE @numbers TABLE
(
      num INT
) 
 
----- Populate a table with numbers 0 to 9
DECLARE @counter INT
SET @counter = 0
 
While @counter < 10
BEGIN
      INSERT INTO @numbers VALUES(@counter)
      SET @counter = @counter + 1
END
 
INSERT INTO numbers (number)
SELECT 
(
      n100000place.num*100000 +
      n10000place.num*10000 +
      n1000place.num*1000 +
      n100place.num*100 + 
      n10place.num*10 + 
      n1place.num
) AS 'number'
FROM @numbers n1place 
CROSS JOIN @numbers n10place
CROSS JOIN @numbers n100place
CROSS JOIN @numbers n1000place
CROSS JOIN @numbers n10000place
CROSS JOIN @numbers n100000place
WHERE n100000place.num < 8 -----  < 800000
ORDER BY number

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