Du kan göra detta genom att byta kolumner om du behöver:
SELECT Col1, Col2, COUNT(*)
FROM
(
SELECT
CASE WHEN Col1 < Col2 THEN Col1 ELSE Col2 END AS Col1,
CASE WHEN Col1 < Col2 THEN Col2 ELSE Col1 END AS Col2
FROM T
) t
GROUP BY Col1, Col2