聚合函数分组

使用group by分组时如果需要显示几个属性值就要在分组中加入

select b.property_name,b.variety, sum(a.whole_num) from tb_stock a, td_product_property b where a.property_id = b.property_id group by b.property_name,b.variety,b.product_info_id

但如果要统计按某一属性的合计时则要使用下列的方法
select b.property_name,b.variety, sum(a.whole_num) over (partition by b.product_info_id)
  from tb_stock a, td_product_property b
where a.property_id = b.property_id