Question

When a set is given say {1,2,3,4,5,6}
The task is to separe pair of subsets

{1,2},
{1,3},
{1,4},
{1,5},
{1,6},
{2,3},
{2,4},
{2,5},
{2,6},
{3,4},
{3,5},
{3,6},
{4,5},
{5,6}

So when i have a table

Table Element
1
2
3
4
5
6

What is the way to list out all possible pair of comma separated subset ?
(Duplicates can be ignored (i.e) {1,2} is identical to {2,1})

Answer 1

SELECT T1.elem, T2.elem
FROM MyTable T1
INNER JOIN MyTable T2
ON T2.elem > T1.elem

…gets you most of the way there – if you want these shown as sets then…

SELECT '{' + CAST(T1.elem AS VARCHAR(12)) + ', ' + CAST(T2.elem AS VARCHAR(12)) + '}'
FROM MyTable T1
INNER JOIN MyTable T2
ON T2.elem > T1.elem

…is what you’re after.