What is the most effective and flexible way to generate combinations in TSQL? With 'Flexible', I mean you should be able to add easily combination rules. e.g.: to generate combinatories of 'n' elements, sorting, remove duplicates, get combinatories where each prize belongs to a different lottery, etc.

For example, Having a set of numbers representing lottery prizes.

Number | Position | Lottery
---------------------------
 12    | 01       | 67
 12    | 02       | 67
 34    | 03       | 67
 43    | 01       | 89
 72    | 02       | 89
 33    | 03       | 89

(I include the position column because, a number could be repeated among different lottery's prizes)

I would like to generate combinatories like:

Numbers | Lotteries
-------------------
 12 12  | 67 67
 12 34  | 67 67
 12 34  | 67 67
 12 43  | 67 89
 12 72  | 67 89
 12 33  | 67 89

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