Mysql学习笔记2

where查询子句： select goods_id,cat_id,goods_name from goods where goods_id in (select max(goods_id) from goods group by cat_id)； 通过where的查询子句能够很好的扩张查询效率，它是内层的查询结果作为外层的比较条件。 mysql> select goods_id,cat_id,g

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