group by后取第一条数据

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       因为在mysql的查询语句顺序上会有先后，先执行group by之后才会执行order by，所以对于以下这种数据：

 我的sql语句是这样写的：

SELECT act_goods.goods_id,goods.goods_name,act_goods.act_price  FROM nata_activity_goods act_goods 
LEFT JOIN shopping_goods goods ON goods.id=act_goods.goods_id 
LEFT JOIN shopping_goods_sku sku ON sku.goods_id=goods.id AND sku.id=act_goods.sku_id

ORDER BY act_goods.act_price DESC 

想获取最低的价格(光标所示)进行group  所以在sql语句order by 之前加上了GROUP BY act_goods.goods_id  但是由于顺序问题导致不会先进行排序在进行group by  所以后来对语句进行了修改，如下：

SELECT b.goods_id,b.goods_name,b.price FROM nata_activity_goods act_goods,(SELECT MIN(act_goods.act_price) AS price,act_goods.goods_id,g.goods_name FROM nata_activity_goods act_goods LEFT JOIN shopping_goods g ON g.id=act_goods.goods_id GROUP BY act_goods.goods_id) b
WHERE  act_goods.goods_id=b.goods_id AND act_goods.sku_id IS NOT NULL GROUP BY b.goods_id