Question

It is possible to write a generic function/procedure/select/somethingElse to cross-join a table against himself ‘n’ times? (yes, ‘n’ is a given parameter : )

How would you do it?

---

Example

Having this table:

 Value
-------
   1
   2
   3 

cross join it 2 times, would return:

 Value  | Value
------------------
    1       1
    1       2
    1       3
    2       1
    2       2
    2       3
    3       1
    3       2
    3       3

Answer 1

Using dynamic SQL, SQL Server 2005+ (@table_name and @numCrossJoins are stored procedure parameters):

DECLARE @upperLimit INT
    SET @upperLimit = 1

DECLARE @SQL NVARCHAR(MAX)
    SET @SQL = 'SELECT * FROM '+ @table_name +' '

BEGIN 

  WHILE (upperLimit <= @numCrossJoins)
  BEGIN

    SET @SQL = @SQL + 'CROSS JOIN '+ QUOTENAME(@table_name) +' '

    SET @upperLimit = @upperLimit + 1
  END

  EXEC sp_executesql @SQL

END