mysql分组，然后组内排序，最后取每组前2条数据

1.首先根据城市分组，然后查询出点赞数为前2的数据

SELECT
	release_city,
	SUBSTRING_INDEX(
		group_concat(
			dazzle_id
			ORDER BY
				week_praise_num DESC
		),
		',',
		2
	)
FROM
	sc_dazzle_dazzle_info
WHERE
	dazzle_state = 1
AND re_status = 1
GROUP BY
	release_city

2.合并这个数据的主键字段为一行

SELECT
	group_concat(dazzle_ids)
FROM
	(
		SELECT
			SUBSTRING_INDEX(
				group_concat(
					dazzle_id
					ORDER BY
						week_praise_num DESC
				),
				',',
				2
			) AS dazzle_ids
		FROM
			sc_dazzle_dazzle_info
		WHERE
			dazzle_state = 1
		AND re_status = 1
		GROUP BY
			release_city
	) a

在这一步获取到的主键数据格式为：

1182,1181,1223,1209,1253,1246,1266,1265,104,103,107,105,1160,1159,1270,1269

3.根据这一行的主键字段查询数据

SELECT
	a.release_city,
	a.dazzle_id,
	a.user_id,
	b.usercode,
	b.phone,
	b.username,
	a.introduce,
	a.week_praise_num
FROM
	sc_dazzle_dazzle_info a 
	LEFT JOIN sc_user.sc_sys_user b ON a.user_id = b.id
WHERE
	LOCATE(
		CONCAT(",", dazzle_id, ","),
		(
			SELECT
				CONCAT(",", group_concat(dazzle_ids), ",")
			FROM
				(
					SELECT
						SUBSTRING_INDEX(
							group_concat(
								dazzle_id
								ORDER BY
									week_praise_num DESC
							),
							',',
							2
						) AS dazzle_ids
					FROM
						sc_dazzle_dazzle_info
					WHERE
						dazzle_state = 1
					AND re_status = 1
					GROUP BY
						release_city
				) tem_a
		)
	) > 0

第散步中将数据变成了
， 1182,1181,1223,1209,1253,1246,1266,1265,104,103,107,105,1160,1159,1270,1269 ,

然后然后再将主键变成,1181,的格式去匹配，既可查询出满足要求的数据