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WITH intLagLead
AS
(
	--Получаем границы диапазонов с привязкой к оригинальному ID
	SELECT Q_ID,
	CASE
		WHEN ISNULL(LAG(Q_ID) OVER (ORDER BY Q_ID), 0) =
			Q_ID - 1
		THEN NULL
		ELSE Q_ID - 1
	END AS intLead,
	CASE
		WHEN ISNULL(LEAD(Q_ID) OVER (ORDER BY Q_ID), Q_ID + 1) =
			Q_ID + 1
		THEN NULL
		ELSE Q_ID + 1
	END AS intLag
	FROM utQ
)
--Вытягваем интервалы.
SELECT intLag, intLead
FROM
(
	--Собираем границы из двух - в одну строку.
	SELECT intLag, LEAD(intLead) OVER (ORDER BY Q_ID) AS intLead
	FROM intLagLead
) t
WHERE intLag IS NOT NULL