查询数据分组之后的前几条数据 可根据不同情况筛选

需求 : 1)获取每个企业新发布的4个产品
2)VIP企业获取8个产品

简单的demo
这是所有的数据

SELECT
    product_name,
    company_id,
    add_time,
    vip,
	rn
FROM
    (SELECT
            product_name,
			company_id,
            add_time,
            vip,
            @rn:=CASE
                WHEN @var_company_id = company_id THEN @rn + 1
                ELSE 1
            END AS rn,
            @var_company_id:=company_id
		FROM  ms_products, (SELECT @rn := 0 ,@var_company_id := 0) AS vars
        WHERE company_id IN (SELECT company_id FROM ms_products )
		ORDER BY company_id ,add_time DESC
	) as products
WHERE
    ((rn <= 4 and vip =0) OR  ( rn <= 8 and vip = 1  ))
ORDER BY company_id,add_time DESC

查询结果

其实就是查询的时候增加个自定义字段rn,并根据该字段筛选排除