SQL取分組中前、後幾條數據

• 最小2個

SELECT
	a.*
FROM
	tb a
WHERE
	2 > (
		SELECT
			count(*)
		FROM
			tb
		WHERE
			NAME = a.`name`
		AND val < a.val
	)
ORDER BY
	a.`name`,
	a.val

• 最大2個

SELECT
	a.*
FROM
	tb a
WHERE
	2 > (
		SELECT
			count(*)
		FROM
			tb
		WHERE
			NAME = a.`name`
		AND val > a.val
	)
ORDER BY
	a.`name`,
	a.val